First up, again thank you odalrick for that tidy piece of work, sorted things out very nicely with a bit of adaptation.
But I don't think anyone would use it. I for my part would buy Spellsphere Level I + Spellsphere Level II to wait a bit until I get enough XP to promote my unit to Spellsphere Level III as I can use 500

a lot of better.
OK, I can see that, but I don't think that getting access to a Level III spell should be any cheaper than it is. As odalrick pointed out however, the main investment here is indeed the time required. The way I've set it up, the unit is held in the city and can't cast spells while it's studying, so you have to do without your arcane unit if you want to put it into training. I'll wait and see what playtesting brings up regarding pricing/timing.
If however it is possible to get the promotions from that spell sphere (which I was uncertain about after reading your post), then these buildings would be worth using a great person on, even without the bonuses, provided that it still allows you to do so after changing your mana nodes away from that buildings mana type after construction.
-Colin
Yeah, it's possible to get the promotions and change the mana afterwards.
Well, glad you like the idea at least!
I'll address the suggestions you made one at a time:
1) World Wonders: I think they're probably better as National Wonders, more from the lore perspective than anything else, as I've described them (in the pedia) as centres of learning within the country. Also, giving one side in a war the training ability while depriving the other seems kinda dicey to me from a balance perspective, powerful World Wonders notwithstanding. If there proves to be a consensus that the effects are too powerful, I can always scale them back or remove them, since I mainly added the effects for flavour.
2) Require mana/tech: I'm a little confused here, they already require these things before the GS can build them, maybe I didn't explain that too well. For example, to acquire the Academy of Bones (associated with Death magic) you need a Great Sage, the Necromancy technology and a source of Death Mana (although you could dispel that afterwards).
3) Require KOE: I presume you mean Knowledge of the Ether? In that case see above, anyone who can build these academies already has this technology.
4) Require "mundane" tech: Hmmm... not sure about this, I suppose Construction/Engineering would be appropriate in terms of lore, but I'm not sure it's entirely necessary. Again, I think I'll wait for some actual playtesting before making final calls on this one.
The point you made about dispelling the mana after building the Academy is valid, but there's a sacrifice there; training a unit at the academy is significantly slower than taking the promotion, so it may not be as powerful as you think. Also, to use dispel, you need the Sorcery tech (unless there's a UU I've forgotten that can do it earlier) which is the magical equivalent of Iron Working by which point there'll be some powerful units/heroes coming out anyways.
The problem with your notion that these are great is that this is Rise from Erebus. That means that these buildings are competing with:
Regular Academies from sages
Great Engineers who instant build wonders
Master Craftsmen (from Great Engineers)
Founding Corporations
Altar of the Lunnotar
Settling great people (which is significantly more powerful than many people truly believe)
Religious Buildings
This means that you have to make it so that it would be worth my while to use a great person on these buildings instead of the ones listed above. On top of that, there are 21 buildings, and the average player is lucky to get more than 3-4 great people a game, 8-10 if they run a specialist economy. This means that these buildings are competing against other uses that could massively boost their economy. At the moment, I would relegate them into the "Cool, but not all THAT useful", and not really aim for them in my usual games. I might try them out in a specific game that I devoted just to that, but just from looking at them trying to get the great people that I would need (and need to devote away from my already running a dedicated specialist economy in most of my games), generally I'm not seeing anything worth devoting a great person too.
Part of the reason why I'm not really seeing much use for them however comes from the fact that for the most part, magic is rather useless. Yeah, it makes things a little easier, and I won't pass it up if I can snatch it for cheap, but aside from terraforming, there isn't anything that magic can do that a big enough stack of champions can't. And I can guarantee you that I will get the big enough stack of champions - I can't guarantee the mages.
-Colin
First of all, I wouldn't expect anyone to get all of these buildings, in fact I can't see much use in that. I intended that they be used to teach some but not all promotions to arcane units, and also to spice up Great Sages, which as it stands lack the special abilities of the others (no master buildings, guilds, only 1 religious shrine).
I can see why you wouldn't go for them if you generally only use magic in a support role, but then it would be equally valid for someone with a playstyle heavily skewed towards using magic to say that the Master Craftsmen are useless, and that he'd rather build one of these academies.
Regarding magic being generally useless, I really can't agree with that assessment. As nikosison pointed out, some spells can eat large stacks of Champions alive. In particular, I submit to you that any force of Champions will most likely lose to a force of equal

value of Mages with Sun II and Death II, since they won't be able to advance or retreat, and will be facing equal or greater numbers of totally expendable units with a strength comparable to their own (especially if the mages are supported with adepts using rust to remove Iron weapons).
I kinda agree with you... but my notions are no less true.
If you make them so great, you won't use regular academy or bulb techs... as the "new" academies would be much more interesting..
...
that's almost balanced... now you add new options for the GS... they have to be balanced with the other propositions, not be better, nor more interesting.
for me those propositions, modified a bit, maybe with my recommandations, maybe with the other propositions for more balance, other effects...Etc are usefuln not as a "I want to build all the magical academies" but as a "I don't want to settle my GS.. what can I do with him ?"
As I observed before, these buildings are quite situational, depending on whether or not the individual uses arcane units a lot. As you put it however, they're intended as something to make the GS more interesting. You're right, they shouldn't be better
in all circumstances but sometimes I think they should, like pretty much everything else.
On the news front, the first version is almost done, so it should hopefully be released soon
