You know I was excited about New Vegas...until I saw some footage. As much as I liked Fo3, I really with they'd fixed the same awkward buggy engine the've been using since Oblivion (which I've only just gotten around to playing.) I know it sound like baseless griping, but I had hoped Vegas would build on what worked and fix what didn't but it just looks like an elaborate expansion pack, so I'll wait for it to turn up cheep in a bargin bin or a Steam sale. No rush.
OE has never had to make their own engine though and probably never well, with the failure of Alpha Protocol. At this point I don't think it's reasonable to expect anything more than great storytelling from them.