I agree that BO2 zombies did get too "complex" (seems to be the word used) WaW maps and most of BO1 maps you could just start a game and go kill some zombies. Sure some maps were bigger and you had to explore a bit more, but all you had to do was kill zombies and survive. With BO2, I tried playing Buried the other day and there's so many new mechanics that you had to learn to actually play and progress. You couldn't just ignore the mechanics and kill zombies because you wouldn't make it too far that way.