Just an idea, but how about a world pvp event to see which faction gains the most fair HK's in a set amount of time or something on a set day? could work for all levels and obviously chars would need to be in fair level range of each other.
some sort of faction prize buff or somthing? I know it sounds a tad like custom content but i reckon it would rock
the name of the game is 'world of WARcraft' after all!
Your thoughts anyone?