Paid DLC in the form of additional campaign levels and cosmetic additions for multiplayer is something I have no problem with. Developers and publishers need to get paid! It's when that need for profits interferes with the sustainability of a game's community that bothers me most.

With free multiplayer maps you'll probably never see that happen unless the game is just absolutely horrible to play to begin with. Adding in campaign stages that you have to pay for shouldn't make you worry about splitting everyone apart because the mode at its heart is a solo adventure. Sure, it might split apart any online cooperative playlists, but that's an okie dokes trade off I think. Not to mention campaign experiences are probably far more intricate and expensive than anything in multiplayer short of the online architecture so getting some revenue is obviously necessary.

Paid cosmetic pieces are totally nothing to worry about. They're just an optional way to set your in-game avatar apart from everyone else with no reflection on skill or ability. It's only the consumer's fault for investing so much in this feature that is in no way integral to gameplay, not the developers.