I didn't think the lack of dedis in mw2 was a dealbreaker, for me it was the sprint speed - it was weirdly slow and the game lacked the pace of mw1 for me.
Black ops was just mediocre all over, and performs like a dog to this day on my system which I'm still a bit peeved about.
WaW had a handful of great maps, the one thats basically like stalingrad kessel from RO for example. But too many pap maps let it down, if you play on a good bolt server with the best of the maps it does go some way to restoring past glories though.
I was thinking of buying MW3, but I do feel that the pc crowd has become apathetic about cod nowadays and I thought that none of the hardcore pc community would be playing which would leave me with a rubbish online community to play with.