Dude I'm probably the only one who thinks WaW>MW when it comes to both online and story mode (although both story modes are average at best) and yeah Treyarch did a great job with the zombie mode. They had a beginners playlist which only match you with people rank 10 and lower, in MW2 I struggled at first, I can't customize my class or have a decent weapon (sorry FAMS sucks) but when you get to level 8(?) you start playing the game and when you finally get Cold Blooded you REALLY start the real game 
About the maps yeah Derail and especially Wasteland can go die in a fire (really Wasteland is seriously horrible) but the rest are fine I think and my favorites are Skidrow, Terminal, Karachi, Afghan, Favela and Quarry (what can I say I have lots of favorites :D)
*Edit* Damn you dbot -_-
