Abandoned and explorable vaults are certainly not the central element of the game - nor should they be - and the series is not called Vaults. There's no implication or suggestion of any kind, that "Yeah, once I load this up, I (should) get to explore abandoned vaults." So I don't really see your point there.
Well, it's the 1&2 supporters that are always saying that stuff "isn't true to the game". The vaults are a big part of the story line. So how would you stay true to the game with very few vaults? I don't think it's good to base the future design of the games, on the assumption that people have played all of them. Because a lot of people haven't. Probably the majority. There's probably going to be a lot of people that will play 4, that haven't played any of the old ones.


I doubt the developers are going to start eliminating stuff that has been a large part of the game, just because some people who have played past versions are tired of it. I'm just looking at it realistically. If game development used that criteria to create new versions of games each time, then COD would have been turned into football or something by now.