Eh, but that would require HM slaves again (which I enjoyed not having to worry about in B/W). Now, if they introduced secret caves/buildings not in the original B/W that didn't require HM's to get access to, I wouldn't mind that. Maybe they can call it "development" or "new discoveries" that happened after the events of B/W.
I do like the idea of new areas within Unova itself... there's lots of room to add extra stuff. I'm not so keen about giving up a team slot for a slave or saddling my Pokemon with HMs that are less than adequate in combat. But, if they add a fifth "slot" for HM moves that can be used in the field but not in battle, then the whole HM thing could very well become viable again.