So without getting into the nitty gritty details yet, this suggestion is mainly focused around PvP and alliances so if that's not your thing I don't want to waste your time!
I have had a thought of possibly making huge alliance battles wherer they could possibly fight over different "Strongholds" around the global map and for these strongholds to grant possible bonuses of some sort (5% increased food production) to all alliance members or something along those lines. You may ask who will fight the battle in the alliance? I thought it could be a good idea for the Leaders of each alliance to select a willing participant and hence they go head to head on the stronghold with their armies. I feel that this could add a new competitive aspect to the game and if this isn't your cup of tea you do not have to be selected to battle. PB:Could there also be a page where people could donate troops and useful items to the two fighters on each side?