I don't know... has anybody done the math on this? I mean, a single point of material could be a huge bonus to production. A point of grain could be crucial to getting your city that extra level.

I LIKE cities with essence and I always choose sites with essence on them. But I do so because spells provide a very dynamic way of altering what a city does. I'm not convinced that essence provide the best solution if I am trying to min-max. How much is a point of essence really worth? Better than a single point of material, or a point of grain. But better than 1grain+1material? I don't think so... but I'm not sure.

It could be a dwarf-like engineer nation which gets double production per material PROVIDED there is no essence in the tile...

What I dont like from essence right now:

It gives grain on a one to one basis if a certain enchantment is cast.

It gives extraordinary amounts of research if a certain enchantment is cast.

It can ignore the prestige/town requirement and give extraordinary amounts of growth

Every enchantment scales with more essence, so the more you have, the better each point of each essence is, 1 point of essence is ALWAYS better than 1 point of grain, since it can give the same benefit, 2 points of essence is better than 1 material and 2 grain. - 3 points of essence is always better than 3 grain 2 production...

Also don't like the essence system because enchanted hammers is earth only, and such a powerful enchantment now.

Not trying to hate on essence, its a fantastic idea, I really like the flow of enchantments, but the balance is whack.

Sincerely
~ Kongdej

And here I thought the advantage of Essence was supposed to be its flexibility. Honestly, number 1 is the only common one, and if there's a complaint about Essence it would be how effectively it boosts Grain/Growth compared to other methods. The production bonus from Enchanted Hammers is miniscule so that's one area you're likely to find an advantage with no Essence plots which have a high material yield. Overall however, yes, you're better off finding a plot with Essence. Just like you're better off finding a plot with better yields all around. It's an extremely valuable resource but it isn't absolutely necessary and not always available.

The Grain Boost effectively lets you make a city with no weaknesses, turning a low food, high material city, into a high food, high material city. Making grain into a dump stat if you have Nature's bounty.  This is the biggest thing to me.

The reverse isnt true about production though. There is no way you are gimped with a 3/4/0 , 4/4/0 or 5/4/0 starting city.  Production is the most important thing out of a starting city, and material is worth far more production than essence.   Once you get your start city, you can seek out +essence locations.

Even a city with 3 material is quickly going to out produce a 4/2 city with 2 essence and enchanted hammers. Material is worth 7 production a piece, and two early buldings, workshop and logging whatever both give +2 per material. Enchanted hammer is only +5 per essence. A nice little bonus, but not preferable to another material just for production. And not everyone has enchanted hammers. Inspiration might make a 1 turn difference in the first couple of techs you get.  My favorite is actually the +mana per essence one, which really lets you jump start early game mana production, especially with Pariden scrying pools.

The nicest things about Essence is versatility.  I like to think of them as slotted magic weapons you can customize, definitely powerful and desirable, but not necessary.  I do like it as a limiter on the amount of simultaneous buffs a city can run.

That said,  I dont like the way City buffs scale with essence, in addition to being more versatile with higher essence. I wish the city buffs were a reasonable flat bonus, or scaled to a lesser degree with some other factor, like shards, and that at a +1 per 2 shards, not a +1 per shard.

My point was, that if the City buffs were less powerful, it would be easier to spread the wealth around, let more locations have some essence, and players would feel better about getting a 1 essence tile. 

Right now it's painful to build a city on anything less than 2 essence, because there's a world of difference in between 1 essence and two, especially if you have Pariden scrying pools, which means 2 becomes 3 essence, which makes for extremely powerful enchantments, and a lot of them.  Cities should have distinctive strengths and weaknesses (everything in a strategy game should). A buff should enhance them, and help customize them, but never replace the need for good specialized stats, or reduce the need to make hard decisions about the city.

To have enchantment Power, and Enchantment Quality both share the same determining number makes it too important, in my opinion. Variety should be one factor, power a separate one. I think the value of essence should come from the number of flat perks you're able to give to a location, not also how powerful those perks are.  As it is now, no player will willingly settle on the majority of inhabitable tiles on the map if they can help it, and inhabitable tiles are already a minority of the map. Being able to have +3 mana, +3 Growth, and +3 grain on each city is too, too much in my opinion, and it diminishes the need for tech, construction, and  hard choices. Especially since at present, the AI doesn't know how to properly value essence for optimal building strategy, seldom insisting their cities have any.

In addition, it's harder to fine tune the power level of a particular enchantment with only a number of 1, 2 or 3, if enchantment are going to scale. Letting them scale in power with something like shards provides room for more granular scaling (because you get more of them).  Or better yet, letting players learn or research more powerful versions of the city buffs, so the Essence benefit isnt so front loaded in the beginning of the game.

Wow that sounds neat. 

I agree that all cities should have access to spell effects. That's just fun and thematic and magical. The problem as it stands is that Essence serves both as an enchantment limiter and an enchantment strength, making the power of Essence essentially squared. Here are a few of my suggestions; note they are not intended to be all used together (though some of them work nicely together), they're just a few ideas.

To increase access to enchantments:

1. Allow any and all enchantments to be cast on a city, with no limit. However, there is a mana upkeep for every enchantment past the essence threshold, either a fairly expensive one, or one that increases with each enchantment. If the upkeep starts at 1 and increases by 1 each time (but "under essence" enchantments are free), then a city with Essence 1 and 3 enchantments costs 3 mana/turn (0 + 1 + 2), while the same city with Essence 2 would only cost 1 (0 + 0 + 1). Alternately, allow Essence to go into the negative, and incur a mana cost for it (probably Essence^2, but maybe just -Essence*5). Powerful enchantments cost more than one essence.
2. Add essence boosters to shard - or other resource - improvements (or their upgrades). I like this one, because intuitively a city lucky enough to have access to multiple shards just *should* be more enchanted, shouldn't it?
3. Add more universally available improvements (optionally costing maintenance) that add essence.
4. Increase all tiles' essence by 1, or enforce a minimum of 1.

If some of these are used, it might be worth devaluing Essence a little, either by making enchantments cost varying amounts of essence, or by weakening the variable power of enchantments, as below.

To address the quadratic power issue:

1. Link enchantment power to something else, like shards.
2. Make the strength difference smaller (f'rinstance, Nature's Bounty adds +1 Grain, and another +1 food per grain per Essence (or Life Shard)
3. Remove variable enchantment strength altogether; Enchanted Hammers is +10% production.

Also, give easier access to curses and disenchants (or uncurses).  Enchantments should be a little more interactive; as is they're more or less fire and forget.  Include a spell resistance attribute for cities, through racial characteristics/garrisoned units, buildings (not all-or-nothing like the Conclave special), enchantments, and/or resource improvements (like nightshade in MoM).

My two bits.