For some reason this idea has bifurcated. One side of it is a relatively conventional fantasy game, complete with dungeons and raiding and the like, developed so it can be played on iPhone/Android/PC/whatever with relative ease. Attached to that would be a territory conquering game for the heavy PvP nuts, but it'd be set up similar to Puzzle Pirates in that you could happily play without paying attention to the territory game. I'd include gear, but not leveling, so that a good player could gear up quickly, and all gear would be crafted by players using materials that (tada) would be produced from conquered territory.
See it all comes together! I think it could be neat. Maybe I will start it eventually.
The other idea is like the above idea, only instead of fighting fantasy-style, all combat is done through ROCKING OUT VIA RHYTHM GAMES. And the world feels like a cartoon version of Brutal Legend. At some point there will be a huge PvP war, and one commander will yell to his lieutenants, "We need those amps taken down NOW!" And they will try, but the amps will be defended by an elite squad armed with Atomic Guitars and wearing Adamantite Studded Leathers of Heavy Metal. Just when the battle is lost, a third faction will send a supersonic flight of glam girls, and through a concerted effort, the war will be won, and the vinyl mines will be captured.
I have not figured out a single sane game mechanic for this second idea - I swear, it's optimally designed for being un-fun - but it makes me giggle every time I think about it.