Agree with Annatar11's reply 1 of this thread on everything but "stat specials" since i imagine it would be too difficult to implement fairly. As for the powerful essence-auras, that might work but is not the theme of this post(unless these auras/specials are built into the mythical creatures or artifacts i describe. Having a cleave attack for 3 essence or spending 3 essence to make a cleaving sword are similar).
Never played the beta, but i plan on buying the game asap and am concerned with wisdom and essence.
Essence-Spent on Special Powers. Remaining pool gives a bonus to stats.
Wisdom- How much magic you can do at once
Intelligence- How strong the spells are. AKA int+1 damage or a 1+Int/2 strength enchantment
I see essence as a measure of the "special power" versus "life force" of a sovereign. He uses up some of a constant life force to gain a (possibly temporary) special thing. Once it is spent, it is gone forever. Every game, each player stats with the same amount of it. For that to work, it has to equally benefit a sovereign that focuses on casting spells, swinging swords, building civilization, or whatever else. For this reason, essence=mana cap does not work for the "swinging sword" variety. (you can say, it lets him use enchantments to do this better, but that makes him a spellcaster hybrid, which is not the theme i want for him.)
90% of the time, you spend essence to distribute your power to the rest of your faction. Imbuing specific land(to make it be more fertile, or to transform the ore in a mountain to mithral), building(to make a barracks spawn troops from thin air, to make a library give some sort of research bonus, or make a smelting factory conjure its own metal), area(spreading fertile land, tactical purposes such as reduced enemy defence/movement, all Allys receive X enchantment while in this area, the imfamous "enchant roads" from MOM), creatures(a nest of magic hounds that you can now build or a graveyard that now produces/lets you produce skeletons), hero(for spell-casting power with mana pool based on wisdom), item(an artifact of immense power; possibly upgrade an existing item to artifact status), individual creature(for a supercharged mythical beast which must be comparable to an imbued hero for this to be balanced)
Maybe include other uses of essence, such as the game-ending spell, or a super fireball-that-destroys-entire-armys(STRONG maybe), or a charm spell on independent factions(forget what those groups are called), or reshaping the world by making your civilization's landmass an island(in one casting. not over 25 castings of a make ocean spell)
Many of these powers would have a variable essence cost depending on how much awesome you are getting out of the power.
Unspent Essence. This pool gives a constant bonus to your base stats in some capacity. My preliminary function would be 1 to 1, as in 10 remaining essence =+10 to each stat. This stat-bonus needs to be so great, that losing even one essence is noticeable and a tough decision. If my suggestion of +1 to all/essence, then only give stat bonuses to the highest 2-3 stats. This bonus should be automatic and not require the player to do anything, but should be aparent with a enchantment tooltip or something. It should basically act as a non-magical constant enchantment.
Through the above stat-boosting, a sovereign that wants to hoard his power will be powerful, whether at casting spells, or being tough. On the other side, a sovereign who pours all of his essence into his empire will be weak and avoid battle. To make this work, the starting stats of sovereigns may have to be reduced to 5's instead of 10's, so they are not initially overpowered, but can become very weak.
I see Wisdom as how many magic things you can do at once. Mana cap= function of wisdom. Enchantment slots = function of wisdom. For imbued heroes, their mana pool is function of wisdom. Seems ridiculously simple to me.
I think it would be really cool for a sovereign to "pour himself" into a weapon, which weakens him too much to use the weapon effectively. Then he could pass the weapon down through his dynasty.
Many of these essence uses give you something you could have got anyway if you spent more time on it. its sort of like a short cut. you could search out a resource, or weaken yourself to conjure it. you could focus on building a defensive army, or use essence to make enemies less effective at attacking you.
I sort of compare spending essence to opening a game-editor and cheating a little.
Few if any of these essence powers should require research in case you aren't a researching hero. the sovereign starts with the spell "Imbue" which can be used on units/land/buildings/nothing(to make an item out of thin air) most anything in his nation to turn it more awesome.
I am very curious about how the rest of you feel about my suggestions on wisdom, intelligence, and essence. If i have overlooked something that one of these stats does, let me know and i will adapt my argument.