What I'm genuinely curious about is the impact of shards. I agree with several of the previous posters that simply having shards poop out 1 mana per turn if you control them is pretty lame. There is limited strategic value in that, and really devalues what they seem to BE according to the Mythos of Elemental.

 

Perhaps another option would be to have a finite number of shards of each flavor spawn on each new map, based upon the size of map and number of players, and distributed evenly, but a distance away from all the cities. Now, I'm going to toss some numbers around here, but they can and should all be variables. On a medium sized map with 6 factions, there would be lets say 12 shards in play (a multiple of four, evenly split between the elements).

 

Each and every one of these shards kicks off 12 mana per turn (2 per faction at the start of game). At turn one, each sovereign draws one mana per shard in play. As soon as a sovereign locates a shard, they begin to draw 2 mana from it. They know where it is, and can focus their near-godly attentions upon extracting more mana. Upon capturing a shard, the controlling player begins to draw 50% of the total output of the shard (6 for this example), and all other sovereigns lose access to the mana generated as it is being mechanically focused to one sovereign. THEN, tech improvements allow the sovereign to draw more and more essence from each of their controlled crystals until they reach the maximum 12 points/turn (or whatever)

 

This system is likely to make shards incredibly valuable and highly contested for magic-oriented players and factions, and also a great target for militarily oriented factions, as breaking shrines at shards will free mana for all casters, and cripple the impacted sovereign's magic income.