The thread I looked at was something about not using the same overworld map feature (or possibly any overworld map for that matter). I think they're all worried about getting another Elder Scrolls with a Fallout theme. I personally don't see that happening.

Seems to me that most of the vocal complainers don't want the series to evolve much technologically beyond what Interplay gave us in 1998. Of course, if Bethesda didn't try to do anything progressive with the game engine, the same people would complain about that. You know, some people just have to bitch.