Essence is indeed a good concept but needs balancing really bad.
For example the building that allow me to increase essence are useless since what I get in the end is twice as many EMPTY spots of essence, they should instead speed up, a little, essence regeneration (a little!)
Then after playing 200 turns in frustration with the opportunity of having 50 points of essence which never reloads, children come along!! They have 200 points of essence which regenerate during battles by 4 each turn!!! OMG, that advantage is already annoying against the computer imagine playing 200 turns in multiplayer struggling for essence (which in French means "fuel" ahaha) ...and suddenly, then, the enemy gets one of those kids!!!
THESE ARE MY SUGGESTIONS:
Nobody should ever be allowed to have more then let's say 30 points of essence, (at least not that easy)
When gaining experience one should be able to improve essence BUT A LOT LESS ESSENCE THAN THEY GET NOW.
The tower of magic should increase essence regeneration (2 each turns or three at the most) instead than doubling essence which I will never be able to regenerate anyway.
No units should regenerate essence (nor heat points) while fighting. It makes no sense that one day they don't fight and don't regenerate and the next they regenerate 50 points by just running around in the battlefield avoiding the confrontation and wasting time on purpose its a big EXPLOIT!
Children should conform to all that, maybe spawning with an UNLOADED amount of essence and they have to wait in order to reload (otherwise they could just appear by surprise and even win a game the very same turn by their own if an enemy leader happens to be around your capital... all that by pure luck! NO FUN after many hours of strategic planning)
On the other hands objects that reload the essence should be a little more frequent (it's a "war of magic" after all why are we always without fuel?)
Maybe certain spells should actually take away essence from the caster (as stated in one of those popup windows that appear when the game is loading). That could give a certain importance and limit certain magic: let's say a major demon summoning spell could costs 20 mana and 5 essence. Essence that would be permanently removed from the caster.
To resume: a little less overall essence and a little easier to reload it.
