**** EPIC POST WARNING *****
Hi Dalamb, & Everyone else reading 
# 1 - Having all the element books is great because they each provide a powerful summonable creature. (sounds good to me but has to be balanced against whatever else you could do with the points; is it enough by itself if all the other criticisms are true?)
# 2 - Having more than one element book is useless because the spells are all duplicates of each other. (well, there's #1 to consider)
# 3 - Having any element books is useless because shards don't do anything (someone confirmed they don't increase spell damage, but do they give the 10% bonus to essence? and doesn't this presume the spells themselves are useless?)
# 4 - Having element books is useless because tactical spells are underpowered (well, what about strategic ones)?
# 5 - Having powerful spells is useless because you have to sit around waiting for mana to regenerate (but it regenerates when you travel, and sometimes you have to wait to regain hit points; do those two things mitigate the waiting-for-mana at all, or are they irrelevant?)
# 6 - Element books are useless because you have to research to use them and you're better off researching military techs. (Uh, you still get spells without any tech research; there's the usefulness-of-spells issue raised in #4. But, if someone believes the spells actually are worth having, they don't need techs to use them -- at least in the Amarian tree; never looked at the one for the Fallen. Shards, on the other hand, do require some research.)
# 7 - You don't need the Enchant book because you can research it (3 techs in the Magic tree -- though there's the issue about whether researching that far diverts you too much from more important techs).
First of all, I like to mention that the subject line was a bit of catch phrase. Also, this actually overlaps with a bunch of concepts. Let me try to flesh it out a bit more.
(Value of Spellbooks in relation to character creation points)
Facts:
* Elemental books cost 3 pts (Which give you access to almost all the spells of that element)
* Summoning (Now removed from start) & Echantment cost 5 points.
* Each Attribute point is worth 3 Character points.
* Isn't the spear worth more than 5 points (sorry can't verify right now)
* Brilliant talent, that gives you +1 Tech per turn, is worth 5 points.
Conclusion:
Just comparing these values (and their worth) it is obvious that there is a balance issue in terms of costs and effect. How could 1 attribute point equal the ability to cast all the spells in a given element? And how could a mere +1 to tech/turn cost more than the 'ability' to cast elemental spells?
In the current state of things, one could easily just take all the spellbooks with very minor sacrifice to other abilities or talents. I would like to see it difficult to be the Jack-Of-All-Magics. If anything creating more unique Elements of magic, would just increase replayability and offer different styles of playing the game. If it trivializes magic since you can take it all. Anyways, i have to be careful for I was about to start talking about another point. (Spell diversity & Uniqueness)
Before moving on the is the point about being able to research the Enchantment spellbook. I find this to be wrong, and wrong again. If you could research "it", it should be linked to so epic quest, where you'd have go kill something to get it. Gaining a new magical book should not be as easy as having some people research 'stuff'.
(School of Maigc &Spells vs. Diversity/Uniqueness)
Facts:
* Each School of magic has it's Attack Spell which causes the same amount of damage.
* Each School of magic has it's own powerful summoning spell. (Summoned pets have identical attributes across schools of magic.) -- I Haven't personally confirmed this running off what contributing posters said
---
* Each School of magic has it's own "destroy" terrain spell. (To Desert, to Artic, To water (Flood), To Mountain)
* Even though there is a Summoning School of magic, all elemental schools of magic have summoning spells...
Conclusions:
Apart from buffs, it appears that the differences between Schools of Magic is trivial at best. The worst being the attack spells since they are a copy paste of each other (your intelligence dictates the dmg). Given the fact that there is no difference between a fireball and lightning strike, it's just a different animation period.
Look at the terrain destruction spells, apart from Mountain and flood (which can block passage), The other 2 (To Desert or to Arctic) have absolutely no purpose whatesoever. Apart from giving you the ability to destroy a resource node. (Why not make an Enchantment spell called, destroy node and keep flood & raise mountain and get rid of Scorch (to desert) and Freeze (to Arctic)?) If terrain had some impact it might be usefull, but it dosen't so for now those spells are mainly for "show" or an extremely intricate way to cut down forest tiles... >.>
And correct me if I'm wrong, but you couldn't even make your empire/kingdom into an arctic wonderland. For the land around your cities reverts to Fallen/Grassland automatically.
Although I agree that each school of magic deserves an "attack" spell. But it dosen't need to be a "ball of wtver" hurled at the enemy. One School could focus more on Debuffs/Curses, while another one has very good unit buffs, another could have very direct single unit dmg (nukes) while the last one could specialize in DOT's & AOE's. Balancing might be not super fun, but It would be well worth it's diversity.
Now, this is a core design choice, so no real point it poking at it too much. But if you are going to make a school of magic called 'summoning' then why give summoning spells to other schools of magic. It's pretty flawed when you come to think about it, it would be as if you could cast an 'earth' spell in Fire School of Magic. I think it was a bad idea to make a school of magic that overlaps with other schools of magic. If anything I'd suggest making a Summoner talent, when the person has bonuses on research Summoning spells and mana/essence costs.
(Mana - Regeneration, Casting & a few ideas)
Facts:
* You gain 1 mana per turn... Yeah...
* Only cost 1 essence for any enchantment (Please correct me if i'm wrong)
* All spells can be cast in 1 turn (same as above point
)
Conclusion:
If Elemental is this magical world coming back to life, where is the magic in it? I would of loved to see Shrines giving you mana per turn, then again they would have to move to a magic pool in which you "stockpile" mana. I love the 'avatar' concept of the ruler, although I think the ruler should play by a different set of rules then other heroes that 'can use magic'.
One of the fears of having a stockpiled mana pool for your Sovereign would be:
"But if you have like 1000's of mana points stored, you'll be able to cast as many spells as your movement allows...
"
True, BUT... Master of Magic had a very good system fleshed out!
Mana was like any other ressource, you could harvest it in magical nodes and also have buildings which would generate some. (Some races even gave you mana as population increased.
) You would invest that Mana into 3 things.
Research - > Pretty Straightfoward, it would determine how fast spells are researched (Not really applicable to elemental at all)
Mana -> This would be the ammount you direct towards your stockpile.
Casting -> Now this is the important part. Be it overland (strategic) spells or Tactical spells, this skill played a major role in them. This was literally "how much mana you could "channel" per turn". So yeah, you could have 100 000 mana points, but if you had a caster skill of 5, you could only expend 5 points of mana during a combat. Not only that, but major spells (which could cost 100's of mana points) would have their casting times based on this value.
So for example, you wanted to cast "City Buff XYZ" and it cost 250 mana. Well if you had a Casting skill of 5, it would take you 50 turns to cast the spell, but if you had a skill of 25, it would only take you 10. 
If there would be ANY way of trying to squeeze this concept inside Elemental, I swear to the gods of TBS games would give us hugs & kisses.
I believe there needs to be a much more severe scaling of mana costs for spells. As it stands all spells can be cast in 1 turn. I like the idea of casting this world altering spell that takes my Sovereign multiple turns to prepare before it is cast.
So this would allow us to have maybe more powerful spells with them being offset by very high mana costs, and casting time.
Same goes for summoning and enchantments. 1 Essence for any enchantment? Regardless of it's strength makes it feel a bit of a trivial cost. One of the ways I think they prevented exploiting this, is limiting the powerful summons from the elemental magics to 1 only per school of magic. I really think Mana / Turn upcost, combined with a mana pool system for the Sovereign would really help balance things.
Epic post is epic,
V