I have to agree with you that IW has gone downhill mate, and to be honest, I don't play CoD WaW at all really, I just feel that it's a better looked after game than MW2.In my opinion the best COD game that has been released was the first one (Call of duty + Call of duty: United Offensive) which was just released on PC, absolutly amazing gameplay, once it started going to the consoles tho it was all about the money.
From my experience treyarch COD's have been the worse ones, IW have recently started to go downhill and ruin the franchise