I love the COD series (MW and BO) but a game a year is getting a little worn out. I think if they took more than 6-7 months to make a game, it would be infinity better. Just in multiplayer it would give them time to fix spawns, nerf guns, put in vehicles, and actually do a bit of testing. Instead we get a half-assed, slightly updated copy of the previous year. Black Ops 2 (so far) looks like its basically the same story as MW3, with different guns and built by a different team.
IMO a longer wait between game would drive up the hype for the next game.
Same goes for EAsports and their NHL series, but that a whole different animal and I don't have nearly enough time.