Actually, I like the dynamic map idea but its probably a real issue for the "win teh war" crowd. I mean, if the map is scaling to numbers, inevitably, you'll have to also scale the proportion of bases - otherwise, those bases already conquered don't count.
EG, at time 1, proportion is 30%/40%/30% knight/bish/rook for 300 players...
at time 2, total players drops to 200... you'd have to retain the percentages or the Bee-oshes would likely be all crabby-wabby and crybabying about not getting credit for having made "big dookie" of the map in their diapers. In fact, knowing them, they'd whine and whine, like some kind of baby denied their bottle.

Otherwise, i'm IN. This one won't end well either and i am shaking my boo-tay for being so awesome

Remember, without me, awesome is just awso.