Hi I'm a big game player, throughout my experience with online games to make a very affective war game you should allow players to duel. Lets say I'm in global chat and some other player says my base would beat yours down, you could click his name and click duel. And a pop up screen will pop up saying John Doe challenged you to a duel. By clicking yes you could access his base and attack and vise versa for him and whoever scores higher with stars and percentage will award the winner with resources like a set amount 10k elixer 10k gold 50 dark elixer. But by doing this you would also have to put in a blockage of same people in alliance dueling eachother so they don't boost that way.