Spell Ideas for the Unimplemented Spheres

[Shatner]

Note: Edited (repeatedly) to include good suggestions and new ideas

The consolidation of magic from the latest patch has left room for additional Spheres of spells to be implemented. And since Kael has shown the poor foresight of actually taking advice from forum posts, I urge you all to add your ideas for what those unimplemented spells should be. As a general rule, try to keep the spells simple and AI-friendly. And Kael, if the design for the Force, Ice, Creation and Dimension spheres is already done, let us know so we can stop clogging the forum with our wish lists.

As always, thanks a ton to the design team for creating an awesome mod. I imagine more than a few of us own Beyond the Sword but have never really bothered playing it as Sid intended (save for the Ice scenario, of course).


Ice
1) Frost: transform plains and grassland into tundra, transform tundra into snow. Everyone wants the lands of the elves to be covered in trees, hills for the dwarves, hell terrain for the Infernals and desert for the Malakim. I think this would allow the "cold civs" to have a similar terrain difference because, let's be honest here, being able to spread terrain favorable to your race is awesome. This spell does necessitate additional changes to the Illians and Doviello to really live up to it's potential (see additional changes section below).

2) Blizzard: like maelstrom but it does ice damage and temporarily terraforms the surrounds into cold terrain, like the End of Winter option.

3) Create Frost Giant: summons a permanent Frost Giant, similar to Wilboman.


Creation - should passively increase production by 3% food by 5% (good idea stp)
1) Fabrication: by having the mage create manufactured goods the local trade routes become enriched. Creates a temporary building which improves trade yields for that city by 50%.
1) Enrich: transforms desert to plains and plains to grassland. See the additional changes section below for balance issues caused by this spell and proposed resolutions for said issues.

2) Transmutation: gold to copper and back, iron to gemstones and back, incense to regents and back. Maybe silk to cotton and back as well. This helps the builder to peacefully acquire missing resources and/or specialize a town for production or commerce. That and allows the incense dependent FoL and regent dependent Veil slightly more options in their resource acquisition. Also, the Kuriotates are the Creation Civ and this spell would help them especially.
2) Cornucopia: creates a temporary Building which grants +4 and retains 20% on population growth. Thanks Xienwolf.

3) Blessing of Amathaon: creates a random resource on the spot corresponding to the terrain it is cast on (more likely to get metal on hill, incense in desert, horse on plains, etc.). The caster loses their Creation III promotion. Creates a temporary building which gives all units built in the city a free promotion. Thematically, just as Amathaon was able to create the greatest dragon, Eurabatres, those watched over by her become paragons of their people.


Dimension - I can see two different approaches to this sphere. One is simply to treat it like every other sphere and try to balance the spells accordingly. The other is to give it a really good passive bonus and then fill it with specialized spells. Metamagic is the sphere for damage dealing mages since it increases their spell damage and reduces the chance of their spells being resisted; I'd like to see Dimension become the sphere for summoners. Make it so every level of Dimensional magic the caster has increases the duration of the summon by one turn OR offers some sort of stat boost to the summoned creature (like heroic defense 1 at 1st level, heroic attack 1 at 2nd and then heroic attack and defense 2 at 3rd level).

--- As a normal Sphere ---
1) Phasing: improves every unit's withdraw chances by a slight amount (10 - 20%). Promotion has a 25 or 50% chance of vanishing each turn.

2) Dimensional Gate: creates the like-named building in the city. Make it so this spell (or the Nexus) is the only way to get this very useful building

3) Banish: sends the targeted unit to another dimension (effectively this kills the unit on the spot). Has the same chance of being resisted as Dominate.

--- As a specialized Sphere ---
1) Escape: this spell isn't very useful but really we're not taking this sphere for the spells

2) Phasing: improves withdraw chances 20%, has a 25% chance of vanishing each turn.

3) Dimensional Summons: casts a random tier 3 summon spell. If it isn't too difficult, have the civilization's mana influence the odds of which spell is chosen (more fire mana means a higher chance of getting a Fire Elemental, for example). Units summoned have the Strong promotion a promotion that grants Dimensional affinity and are picked completely randomly from all tier 3 summon spells.


Force - every unit produced has a cumulative 3% 10% chance of starting with one or more energy resistance promotions (consider it a specialized form of the passive bonus of chaos mana)
1) Mage Armor: grants the caster a promotion identical to the Magic Resistance promotion but which gives them +20% resistance to every energy type and can be removed by Dispel Magic

OR​

1) Magic Missile: targets the strongest enemy unit within two squares and does minor damage. Can not damage a unit below 75% health.

2) Force Push: like the old whirlwind spell

3) Favor of Dadga: grants each unit in the stack a promotion which makes it so the combat odds against them can never be below 50% (I think there was a Chaos spell that used to do this). Promotion has a 50% chance of vanishing each turn.
3a) Disintegrate: targets an enemy unit within 2 or 3 tiles of the caster and does 25 - 50% damage with no damage cap (so it can kill a unit). If the unit happens to be in a city than the spell reduces the city defense by 15%. To determine the target, every enemy unit in range has their strength compared WITH any city defense bonuses factored in and the highest number is picked. This gives preferential targeting to city defenders so you can capitalize on the spell's bombardment aspect as well. The idea is that the archmage is negating the charge of the electrons within a substantial portion of the unit (and possibly the town's fortifications). With the strong binding force temporarily nullified, matter sloughs off the affected area and scatters into it's component atoms, appearing to crumble and vanish to the observer. Or, if that is too much science for a fantasy setting, it simply destroys matter (conservation of energy be darned).

AND​

3b) Avatar of Force: gives the caster +9 strength and Force affinity 1 for one round. This spell is gained when the caster first gains the Force 3 promotion and is lost after it's first use (making this like Lichdom for the Death Sphere since you are only casting that once per Death 3 caster). Basically, the archmage becomes a super-charged attacker capable of stomping on all but the most exemplary defenders... once and only once. This restriction would probably be enforced by having the unit gain a promotion after using the spell which disallows further uses of the spell. If anyone thinks of a more elegant way to enforce this, I'm all ears.

Additional proposed changes to balance the new spells against the other spells​

1) to make the Creation 1 spell Enrich worthwhile, replace the Water 1 spell Spring with Water Walking and create a new the new spell Oasis for Water 2. Oasis would create an oasis on the tile but could not be used within 2 or 3 squares of another oasis (like the Pirate's Cove improvement). This way there would be a water spell that actually spread fresh water to additional tiles.

2) to prevent Vitalize from being weakened by Enrich, replace it with two Nature 3 spells: Terraform: Heat and Terraform: Chill. Terraform: Heat would transform ice into tundra, tundra into grassland, grassland into plains and plains into desert. Terraform: Chill would work the other way (desert -> plains -> grassland -> tundra -> ice). That way people can access all manner of lesser terraforming spells (Scorch, Enrich and Frost) at a relatively small opportunity cost and in so doing gain a limited control over their terrain. However, if they really want to fine tune the ground they're ruling over they need to invest in nature magic. Also note that I am looking for better names for these two spells than "Terraform: Heat and Chill". Any suggestions?

3) as is, Frost doesn't serve a real purpose beyond spreading favorable terrain for the Doviello and Illians to fight on. Like Scorch for the Malakim, you want a No Mans Land of favorable terrain around your empire but not actually in your cities fat crosses (since said terrain sucks yield-wise). I don't really like that; the elves can't cram enough forests in their fat cross and the dwarves generally want hills aplenty. To encourage the Illians and Doviello to use the spell domestically I would have their palaces make tundra yield one extra food (equivalent to grasslands) and snow yield one extra food and production (equivalent to plains). This is functionally similar to the Lanun palace's improving the food yield of water tiles. I'd even like for the Illians and Doviello to be able to build improvements on tundra and ice as though they were grassland and plains respectively but I don't want to ask too much.

4) Creation mana should probably be unlocked with the Sorcery technology, like Metamagic mana. This is partly because Enrich is very powerful as a 1st level spell AND to give the Kuriotates an early domestic advantage since they should receive Creation mana from their palace (they being the creation civ).

 

[xienwolf]

Creation 2: Temporary Building which grants +4 and retains 20% on population growth (I would say 40%, but that would allow the Calabim to retain 100%!)

I kinda like your Creation 2, but you aren't CREATING, just changing

 

[Avahz Darkwood]

couldnt that crush your large cities once you send you mage to battle, etc? Loosing all that food when the building expires?

Creation 2: Temporary Building which grants +4 and retains 20% on population growth (I would say 40%, but that would allow the Calabim to retain 100%!)

I kinda like your Creation 2, but you aren't CREATING, just changing

 

[Maniac]

For Ice I think a spell which would temporarily turn water into ice a usefull spell. It would allow you to march armies over some small divide of water without needing boats.

Probably not AI-friendly though. Perhaps they could get Water Walking, to be removed upon walking on land again.

 

[odalrick]

For Ice I think a spell which would temporarily turn water into ice a usefull spell. It would allow you to march armies over some small divide of water without needing boats.

Probably not AI-friendly though. Perhaps they could get Water Walking, to be removed upon walking on land again.

Summon Ice Floe ? A permanent slow water transport.

 

[Maniac]

Problem is it could be attacked by ships then.

Edit: never mind, it could always be set to be unattackable. Except by fire/sun magic of course.

Edit: Still, it wouldn't be the same. You couldn't just walk over your units then. You'd have to load/unload them. So surprise attacks would be less possible.

 

[Psychic_Llamas]

Ice
1) Frost: transform plains and grassland into tundra, transform tundra into snow (I think the Illians and the Doviello should be able to treat tundra as grassland and snow as plains (and maybe ice as normal coast/ocean), making this spell actually useful for them). Also, everyone wants the lands of the elves to be covered in trees, hills for the dwarves, hell terrain for the Infernals and desert for the Malakim. I think this would allow the "cold civs" to have a similar terrain difference because, let's be honest here, being able to spread terrain favorable to your race is awesome. This spell does necessitate additional changes to the Illians and Doviello to really live up to it's potential.

2) Blizzard: like maelstrom but it does ice damage and temporarily terraforms the surrounds into cold terrain, like the End of Winter option.

3) Create Frost Giant: summons a permanent Frost Giant, similar to Wilboman.

i like all of these, but id prefer blizzard to actually create the blizzard feature from age of ice that roams around turning terrian to tundra and damaging stuff

Creation - i
1) Fabrication: by having the mage create manufactured goods the local trade routes become enriched. Creates a temporary building which improves trade yields for that city by 50%.

2) Transmutation: gold to copper and back, iron to gemstones and back, incense to regents and back. Maybe silk to cotton and back as well. This helps the builder to peacefully acquire missing resources and/or specialize a town for production or commerce. That and allows the incense dependent FoL and regent dependent Veil slightly more options in their resource acquisition. Also, the Kuriotates are the Creation Civ and this spell would help them especially.

3) Blessing of Amathaon: creates a random resource on the spot corresponding to the terrain it is cast on (more likely to get metal on hill, incense in desert, horse on plains, etc.). The caster loses their Creation III promotion.

not a fan of these. in my mind creation is all about the birth of erebus and new life and well... creation.

i would rather something like:
Creation - passive ability is something like summons have a 5% chance of becoming permanent.
1) Summon Nymph: summons a nymph that can be tied to the terrain it is cast on. the nymph may sacrifice itself to build an feature called 'natural spring', which provides fresh water to surrounding squares and adds +2 food the the tile. can only be cast on tiles without access to freshwater, and not next to coastal tiles. the nymph is also a permanent creation affinity 0.5, move 2 summon that can cast spring (with access to water mana) and scorch (with access to sun mana).

2) Summon Dryad: strength 3, move 1, Nature affinit 1, creation affinity 1 summon. starts with woodsman 1 and 2, ignores terrain movement penaltys, can cast bloom (with access to nature mana).

3) Landscape: has a % chance to randomly raise or lower the terrain surrounding the caster. Hill becomes either flatlands or mountain, flatlands becomes either coast or hill. mountain becomes hill, coast becomes flatland desert. The caster has a 40% chance of losing their Creation III promotion.

Dimension - I can see two different approaches to this sphere. One is simply to treat it like every other sphere and try to balance the spells accordingly. The other is to give it a really good passive bonus and then fill it with specialized spells. Metamagic is the sphere for damage dealing mages since it increases their spell damage and reduces the chance of their spells being resisted; I'd like to see Dimension become the sphere for summoners. Make it so every level of Dimensional magic the caster has increases the duration of the summon by one turn OR offers some sort of stat boost to the summoned creature (like heroic defense 1 at 1st level, heroic attack 1 at 2nd and then heroic attack and defense 2 at 3rd level).

--- As a normal Sphere ---
1) Phasing: improves every unit's withdraw chances by a slight amount (10 - 20%). Promotion has a 25 or 50% chance of vanishing each turn.

2) Dimensional Gate: creates the like-named building in the city. Make it so this spell (or the Nexus) is the only way to get this very useful building

3) Banish: sends the targeted unit to another dimension (effectively this kills the unit on the spot).

--- As a specialized Sphere ---
1) Escape: this spell isn't very useful but really we're not taking this sphere for the spells

2) Phasing: improves withdraw chances 20%, has a 25% chance of vanishing each turn.

3) Dimensional Summons: casts a random tier 3 summon spell. If it isn't too difficult, have the civilization's mana influence the odds of which spell is chosen (more fire mana means a higher chance of getting a Fire Elemental, for example).

love the specialised ideas for this

Force - every unit produced has a cumulative 3% chance of starting with one or more energy resistance promotions (consider it a specialized form of the passive bonus of chaos mana)
1) Mage Armor: grants the caster the Magic Resistance promotion

2) Force Push: like the old whirlwind spell

3) Favor of Dadga: grants each unit in the stack a promotion which makes it so the combat odds against them can never be below 50% (I think there was a Chaos spell that used to do this). Promotion has a 50% chance of vanishing each turn.

id rather have the old 'Magic Missile' to replace mage Armour, a low damage spell.

 

[jimi12]

i like the idea of fleshing out the spell spheres. creation mana is more fertility though since amathaon is the godess of fertility (creation) so it doesnt really fit to have it increase production

 

[Charybdis]

id rather have the old 'Magic Missile' to replace mage Armour, a low damage spell.

I cast magic missile at the darkness!

 

[Stephenc369]

How about these:

Dimensional 1: Escape - teleports caster to capital
Dimensional 2: Teleport - teleports caster to any space on the map (or within x squares)
Dimensional 3: Wormhole - move the caster and his entire stack to any space on the map (or within x squares)

I wonder if the paradrop function from BtS could be used for the teleporting.

 

[stp]

3) Dimensional Summons: casts a random tier 3 summon spell. If it isn't too difficult, have the civilization's mana influence the odds of which spell is chosen (more fire mana means a higher chance of getting a Fire Elemental, for example).

I like this idea for flavor, but I can see a clear problem with it from a gameplay point of view: Why would I want to cast a spell that could give me a summon with useful affinity when I can instead cast a spell that will give me that summon.? Or to stick to your example: When you have a lot of fire mana your spellcasters will get appropriate fire promotions for free, so why would you cast a spell that could give you a Water Elemental or anything instead of the desired Fire Elemental, when you can use the same spellcaster to summon a Fire Elemental directly? That said, the Dimensional summons spell needs some serious boost to be a viable option.

For example you could give them additional extended duration to creatures summoned via this spell, or make them the only ones with extended duration.

 

[zxcvbnm]

How about Creation allowing terraforming with the right second mana type? So to make rivers need Creation and Water, to raise hills need C and Earth and to make deserts need C and Sun? (perhaps not that though, but positive terraforming could require it)

Genesis could (should actually) require creation mana.

 

[Algeroth]

Or the spell could give them random promotions, like the mutation spell.
Or the +1 dimensional affinity on this summons.
or +1 duration affinity...

 

[Psychic_Llamas]

How about Creation allowing terraforming with the right second mana type? So to make rivers need Creation and Water, to raise hills need C and Earth and to make deserts need C and Sun? (perhaps not that though, but positive terraforming could require it)

Genesis could (should actually) require creation mana.

thats kinda what i was thinking with the nymphs and dryads thing. and on the note of rivers, i think it is physically impossible to have a spell create a river on the map, i asked a similar question ages ago and was told its impossible because of the way rivers act.

so what does everyone think of my creation mana ideas?

 

[TheJopa]

For Force - a spell that temporary removes all 'elemental' strengths? So Wraith (5+5 death) that is affected by this spell would be just str. 5.

 

[stp]

not a fan of these. in my mind creation is all about the birth of erebus and new life and well... creation.

i would rather something like:
Creation - passive ability is something like summons have a 5% chance of becoming permanent.
1) Summon Nymph: summons a nymph that can be tied to the terrain it is cast on. the nymph may sacrifice itself to build an feature called 'natural spring', which provides fresh water to surrounding squares and adds +2 food the the tile. can only be cast on tiles without access to freshwater, and not next to coastal tiles. the nymph is also a permanent creation affinity 0.5, move 2 summon that can cast spring (with access to water mana) and scorch (with access to sun mana).

2) Summon Dryad: strength 3, move 1, Nature affinit 1, creation affinity 1 summon. starts with woodsman 1 and 2, ignores terrain movement penaltys, can cast bloom (with access to nature mana).

3) Landscape: has a % chance to randomly raise or lower the terrain surrounding the caster. Hill becomes either flatlands or mountain, flatlands becomes either coast or hill. mountain becomes hill, coast becomes flatland desert. The caster has a 40% chance of losing their Creation III promotion.

so what does everyone think of my creation mana ideas?

OK since you asked: I'm not sure about your nymph and dryad (Plus from what I know there is no 0.5 affinity at the moment).
Your Landscape spell sounds a little bit to chaotic. There are only few situations where I would want to cast that spell and most of the time the benefit simply isn't worth the risk in my opinion. In addition, I fear it would be horrible to teach the AI how to decently use this ability.

As for the passive effect, Permanent summons when you just want cheap troops are sound odd and do not fit so well from a lore perspective: Summons are mostly called from other plains and not truly created. It could however fit as a passive effect for dimensional mana.

I would prefer something like a small food bonus. A 5% food bonus per city would fit thematically, as it would benefit the Kuriotates, who represent the creation sphere, more than other civs - their supercities have a higher food total.
I do however fear that this could be overpowered.

 

[Shatner]

I like this idea for flavor, but I can see a clear problem with it from a gameplay point of view: Why would I want to cast a spell that could give me a summon with useful affinity when I can instead cast a spell that will give me that summon.? Or to stick to your example: When you have a lot of fire mana your spellcasters will get appropriate fire promotions for free, so why would you cast a spell that could give you a Water Elemental or anything instead of the desired Fire Elemental, when you can use the same spellcaster to summon a Fire Elemental directly? That said, the Dimensional summons spell needs some serious boost to be a viable option.

For example you could give them additional extended duration to creatures summoned via this spell, or make them the only ones with extended duration.

My initial Dimension 3 spell was going to be some sort of airlift/teleportation effect. Then I realized that your archmage would have to invest a lot of promotions in a sphere which, while boosting the power of your summons, didn't actually allow you to summon anything. So the uber-summoner would be an archmage with Fire 3 who then spent the next 3 levels getting Dimension promotions. That's a problem. I changed the Tier 3 spell to the random summon because that way an archmage with just Dimension 3 can still summon something beefy, thus validating it's existence. However you don't want Dimension 3 to render the other spheres obsolete (if you had a Dimension 3 archmage and a Fire 3 archmage summon Fire Elementals, the Dimension 3 summon would be better than the Fire 3 version) so you make it unreliable in WHAT it summons. Since Dimension is the meta-sphere of summoning I envision a Dimension mage frantically opening a portal to SOMEWHERE to get SOMETHING to come out to fight the Bannor charging him. That said, I see your point about having more mana causing the archmage to already know the summoning spell for that sphere. Then I'd just have the Dimension 3 spell summon a random tier 3 unit without regard to the civilizations mana. Kind of like the old Imp and Genie summons where you would try it each round to get access to something (in that case spells, in this case specialized summons) you didn't otherwise have.

How about Creation allowing terraforming with the right second mana type? So to make rivers need Creation and Water, to raise hills need C and Earth and to make deserts need C and Sun? (perhaps not that though, but positive terraforming could require it)

Thematically we want the Creation sphere to create stuff. This is actually a difficult thing to accomplish while making the Creation sphere simple and functionally unique because we already have other spheres that have been creating things since before Shadow was released. Others have been doing Creation's job for a while, so to speak.

The purview of Creation should be any combination of the following: making units from nothing, terraforming, improving tile yields/creating resources, improving health, improving wealth. However most spheres can summon units, permanently in some cases. Nature, Water, Fire and Sun all terraform the landscape. Life (passively) and Nature (making forests) improve health and RoK increases wealth. The only thing left over is making resources/improving tile yields but that hasn't been implemented yet for good reason; it's a dangerous concept to add into the game.

A huge part of the game is trying to get the richest terrain within the fat cross of a city. This is why City of 1000 Slums, the vitalize spell and FoL are considered useful; resources are placed randomly and rarely so you have work hard to optimize your city. The main schtick of the civilization that worships the god of creation, the Kuriotates, is that they have a larger fat-cross than anyone else. If there was a creation spell that increased the yield of a tile then suddenly the best strategy is to spam that spell EVERYWHERE. It would be very easy to implement but it would ultimately be game breaking. And I can't think of a simple way for it not being game breaking; I don't actually like my Creation 3 spell but I ran out of better ideas. So I tried to go that route as little as possible. Instead, I made Creation spells that do something no other spells do (increase trade yields, change resources, create resources but with heavy limitations). Thematically it's a stretch but it works simply without undermining game balance.

That said, I like the idea of adding fresh water to a tile but that seems like Water should already do that. Actually, I wouldn't mind seeing Water Walking become the Water 1 spell (it's not worth a tier 2 spell slot) and Water 2 become Oasis which creates the oasis improvement on the tile. Make the spell not be castable within 2 or 3 squares of another Oasis (like the Pirate's Cove improvements) and it would be both balanced and thematic (bringing fresh water to a dry tile). Then you could make Creation 1 Enrich which turns desert to plains and plains to grassland.

 

[zxcvbnm]

Thematically we want the Creation sphere to create stuff. This is actually a difficult thing to accomplish while making the Creation sphere simple and functionally unique because we already have other spheres that have been creating things since before Shadow was released. Others have been doing Creation's job for a while, so to speak. .

The purview of Creation should be any combination of the following: making units from nothing, terraforming, improving tile yields/creating resources, improving health, improving wealth. However most spheres can summon units, permanently in some cases. Nature, Water, Fire and Sun all terraform the landscape. Life (passively) and Nature (making forests) improve health and RoK increases wealth. The only thing left over is making resources/improving tile yields but that hasn't been implemented yet for good reason; it's a dangerous concept to add into the game..

My idea was that those spheres would no longer be enough to terraform, but would also require Creation, so terraforming would be less common.

A huge part of the game is trying to get the richest terrain within the fat cross of a city. This is why City of 1000 Slums, the vitalize spell and FoL are considered useful; resources are placed randomly and rarely so you have work hard to optimize your city. The main schtick of the civilization that worships the god of creation, the Kuriotates, is that they have a larger fat-cross than anyone else. If there was a creation spell that increased the yield of a tile then suddenly the best strategy is to spam that spell EVERYWHERE. It would be very easy to implement but it would ultimately be game breaking. And I can't think of a simple way for it not being game breaking; I don't actually like my Creation 3 spell but I ran out of better ideas. So I tried to go that route as little as possible. Instead, I made Creation spells that do something no other spells do (increase trade yields, change resources, create resources but with heavy limitations). Thematically it's a stretch but it works simply without undermining game balance..

How about this:
Creation III
can create resources, only with the right 2nd mana type (nature for organics, earth for minerals) on level III, lose Creation III (and perhaps the other sphere III too) when casted. This would theoretically allow mankind to act gods but it would be extremely difficult to do it on grand scale.

That said, I like the idea of adding fresh water to a tile but that seems like Water should already do that. Actually, I wouldn't mind seeing Water Walking become the Water 1 spell (it's not worth a tier 2 spell slot) and Water 2 become Oasis which creates the oasis improvement on the tile. Make the spell not be castable within 2 or 3 squares of another Oasis (like the Pirate's Cove improvements) and it would be both balanced and thematic (bringing fresh water to a dry tile). Then you could make Creation 1 Enrich which turns desert to plains and plains to grassland.

If rivers won't work then this could be a good alternative.

 

[Shatner]

Eurabatres is the most awesome and powerful dragon because it (he? she?) was created by the Angel of Creation. It makes a certain amount of sense that the Angel of Creation could create things better than any other. So, what if the Creation 3 spell was "Blessing of Amathaon" or "Paragon" and it created a temporary building which gave all units built there a free promotion. The thematic reasoning is that the people raised in a city watched over by Amathaon are bigger, stronger, smarter and all around better examples of what their species is suppose to be. Orcs are orcier, humans are humanier and elves... you get the point. I also like it mechanically because it is powerful enough to be a tier 3 spell AND it encourages the creation archmages to stay in cities (which seems appropriate to me).

My idea was that those spheres would no longer be enough to terraform, but would also require Creation, so terraforming would be less common.

How about this:
Creation III
can create resources, only with the right 2nd mana type (nature for organics, earth for minerals) on level III, lose Creation III (and perhaps the other sphere III too) when casted. This would theoretically allow mankind to act gods but it would be extremely difficult to do it on grand scale.

I like the way you are trying to balance the feature of improving tile yields. However, the topic of multi-mana requirements for certain spells has been brought up a few times and been shot down for being too difficult to implement and too complex for the AI to use. Again, I like your ideas but I don't think it'd fly with the design team. And I'd really like to see the AI terraforming some day...

 

[zxcvbnm]

That might be another cool C3 spell