At least, I thought of giving Nga and Banung an upgrade each. So Nga would upgrade to get Immortal abilities and Banung to get Heheishur ones, being respectively a War Kha and a Heishur.
Not sure if it's good idea. Some time ago there was a thread about upgradeable heroes in FFH forum and it wasn't considered a good idea by most. Currently, only upgradeable hero I know about is Alcinus and he have serious drawback in addition to not having hero promotion at all.
What about Kha? I have some ideas about them... Thought I would only work on them for next version but I'm thinking it might be judicious to put them in right now.
I'd like to hear some ideas on them before throwing out mine; just a trail: I have Kha, War Kha and Divine Kha.
Not much right now, but I see them as bards among Ngomele. Most of the gnoll society is not even thinking about leaving their hunting grounds and are not intrested in ways of other nations, but they need some information about surrounding civilizations. So maybe Kha are only ones leaving their territory to bring tales about other nations. In game, it might be represented by giving Kha ability to tell different tales. One that was in Amurite city can create 'tales of might wizards' building, that gives +1 xp to arcane units. Just a thought, not much thinking put into this
For this though, I'd need the above document to be completed. I want to have all the spells sorted out before doing anything
I was thinking about general design of shurs and I thought: what if different shurs were used for different purposes ? Right now, we have Nature, Body and Spirit. Maybe Nature shurs might be pure spellcasters, body shurs melee warriors and spirit ones be utility ones. In fact, existing spells almost support this version. Let's see:
Oh, one more thing - I don't want to sound like someone who's trying to force his vision

I know that's a lot of ideas, but they are only ideas - it's your mod, after all

And please, forgive any grammar and spelling mistakes - I'm not used to write anything longer than few sentences in english.
Nature: Nature shurs are great spellcasters, who can turn tide of battle with their offensive spells and summoned creatures. They are closly tied to land and feel best when in favourite environment. Thet excel in area damaging spells and summoning creatures. While not best in hand to hand fighting, they have some abilities that allow them to survive direct combat. They lack meditation of Spirit shurs but they make up for it with their bond with land - the more time they spend in they chosen environment the more powerful they become. All Nature shurs share two abilities - affinity towards chosen terrain and ability to summon animals. Affinity gives them small chance (5%?) to gain 1 xp every turn they spend in chosen terrain. Animal summoning allows them to summon animals native to their terrain. This ability works only in this terrain and grows in power when shur achieves new level of chosen Wave. There are three Waves of Nature Coast:
- Sky. Sky shurs feel best when under an open sky, on plains or grasslands. They wield power of air and lightning. They are also good at avoiding enemies thanks to their speed.
1) Summon animal: summons animals native to plains and grasslands and maybe flying creatures. Passive: 20% withdraw chance.
2) Binding Winds: Adds promotion to enemies in range that deals them damage every time they move (is it possible at all?). Passive: Affinity for plains and grasslands.
3) Surrounded by Storms: deals a little of lightning damage to all units in range, and autocast it again next turn (the way pillar of fire works). Passive: 50% withdraw chance.
4) Storm Dance: summons ((Level/2) + rand(0,(Level/2))) small storm elementals. Passive: shur can fly.
- Mountain. Mountain shurs feels best when in hills or mountains. They are tough and hard to kill. They can protect their allies or hurt enemies using earth itself.
1) Summon animal: summons animals native to hills and mountains. Passive: Gains Defensive promotion (double fortification bonus)
2) Shell of Stone: fortifies all units on tile. Passive: Affinity for hills and mountains.
3) Magnetic Surge: hurts units with metal weapons and the like (the more, the stronger). Passive: +2 defense strengh.
4) Animate Mountain: turns a peak till into a hill and summons a Living Moutain unit. Passive: can enter mountains.
- Leaves (it's seems your first idea was better

. Leaves shurs feel better among trees then elves. They understand ways of forest and it's denizens and can use their help to hurt enemies. They despise all things unnatural and are prepared to fight those abominations.
1) Summon animal: summons animals native to forests. Passive: can take one animal companion.
2) Awaken forests: turns all surrounding forests into Awakend Forests for 1-3 turns. Enemies that enter those forest take severe damage. Passive: Affinity for forests.
3) Hurt Unnatural: deals severe damage to demons and undead and little damge to all other. Units with FoL religion are immune. Passive: 25% resist to all elements.
4) Awaken Nature Avatar: summons powerful elemental with massive strengh and bonuses to forest combat. Passive: immune to poison, holy and death damage.
Body: Body shurs are great warriors and hunters. They use magic to increase they fighting abilities, sharpen senses or even to change their bodies. While they can't command forces of nature like Nature shurs, their fighting prowess is matched by few. There are three Waves of Body Coast:
- Claws. Claws shurs are among most reckless and powerful warriors among Ngomele. They don't care about their safty as long they can kill their victim. They are also master hunters and they don't really care whether prey is an animal or a human. And even when they can't kill target, they can weaken it severly.
1) Spell: shur gains special version of rabbies promotion, that dissapears ofter one turn, but can pass normal rabbies promotion in combat. Passive: +50% vs Animals, +25% vs Orcs.
2) Rage: gives +25% strengh this turn but adds fatigued next turn. Passive: +1 Attack, -1 Defense
3) Blood of Green Sea: +2 poison combat, +20 collatoral damage, 25% to wear off each turn. Passive: hidden with stealth when in forest (I believe dark elfs do this)
4) Master of the hunt: adds marksman promotion for one turn. Passive: +1 attack, -1 defence (so +2/-2 total)
- Flesh (probably needs new name). Flesh shurs are able to change their body. They can't use powerful forms druids do, but can change into many animals to enchance their combat abilities. They can also alter their bodies so they heal faster and are not affected by diseases.
1) Recovery:heals +10% per turn until fully healed. Passive: +5% healing from combat.
2) Shapeshift into hyena: 4 strength, 2 moves, Cannibalize. Passive: Immune to diseases.
3) Shapeshift into bear: 8 strength, 1 move, can gain Adrenaline promo after combat, allowing to attack once more. Passive: can heal while moving
4) Shapeshift into tortoise: 16 strength, 1 move, can bombard cities. Passive: +10% healing from combat.
- Eyes. Thanks to magic that sharpen their senses, few beings in Erebus can hide from well-trained Eyes shur. Being great scouts and sentinels, they spend much of their time guarding borders of Ngomele lands.
1) Spell: adds sentry1 to units in stack. Passive: immune to first strikes.
2) Spell: blinds and gives -100% withdraw to units in range. Passive: +1 visibility.
3) Spell: Adds +3 first strikes promotion to units in stack. Unlike dance of blades, it doesn't wear of. Passive: +50% vs Illusions.
4) Divination: reveals location of high (6+?) level enemy units. Don't know if it's even possible - Scions can find Alcinus this way, but it seems rather different. Passive: Can see invisible.
As you can see, there's a lot of synergy within Coasts - shapechanged shurs still can use it's Claws abilities if have both Waves, Nature shur with all 3 Waves level up rather quickly on forested grassland hill. And they are playing diffrent roles in game, probably to even further extend than mages of normal civs.
I like current Spirit Coast, but don't have ideas for Creation Wave. Every idea I can think about is somehow connected with manipulating dreams of other beings ;>