If you ask me, a game like Resident Evil 4 shouldn't have been a Resident Evil game. There isn't much reason for why it shouldn't have been a new IP, apart from Capcom wanting sales from the name recognition. Many fans are still unhappy about the lack of horror in recent Resident Evil games, so why not just have made the "new" Resident Evil games an IP of their own?
I think it's awesome that Modern Warfare 2 is no longer a Call of Duty game. They are shedding the WWII roots, and going for a new series of games (and I pray that Treyarch get to stay with the Call of Duty name, and not follow Infinity Ward). It also means we don't get as many iterations of the same game.
I would much rather see more new IPs than just rehashes of old games. Let the old games stay what they are, and bring new and refreshing things.
Fighting games is a bit of an oddball though, because they are made primarily for the arcades, and don't rely on story, but I would much rather see new IPs in that genre as well, than just old names on new games.