I realize this isn't the case with all of them, but a lot of the time, they're really hard on the new games solely because they're different. There's no reason for that. You can't play the same game over and over again without getting bored and wanting something new. Look what happened with Mega Man.
Oh yeah. Resident Evil fans are like that, too. Anyway, are you guys like that? I prefer to just play the game and decide if I like it or not, and not expect it to be like the first one. I go into a sequel expecting at least one gameplay mechanic different form the previous one, and I feel that's a reasonable request.