Heh, that pretty much sums up my experience with Halo 2. Loved the first one so goddamn much, got to Part Deux, was assmad for the next 7, going on 8, years over all of the changes.
I only played *some* of the campaigns for CoD 2 and 3. They were alright, but they weren't my favourite type of game. I can't comment on the multiplayer.
What I do know is that before CoD 4, Battlefield was king of military multi-player shooters outside of Counter-Strike. One might surmise that DICE's success with a departure from WWII in BF2 is what inspired Infinity Ward to take a gamble by doing the same in CoD 4. If I remember, there were reports of Activision being a bit squeamish about leaving WWII for modern day.
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