for @drugwars peeps

I agree with the above..

I would add that since you have a 'rating' for each player, I am assuming on what levels all their building are, you can easily set up a deal like with other PvP where only certain 'levels' can attach each other..

Or really throw your ninja-dev work into having a mini-game for the battles so there's some actual human interaction and the possibility of actually challenging and fighting each other..