J.E sawyer compared the transition from F3 to new Vegas as being similar to transition between GTA3 and vice city.
The thing that bummed people about vice city was that the map size wasnt as big as people thought. I hope this game has a decent map size.
While we're on the subject of Grand Theft Auto, GTA: San Andreas showed me that there is such a thing as too big. Anytime I had a mission or just some random mayhem I wanted to cause somewhere, the location was within a few comfortable minutes of (reckless) driving in GTA3, Vice City, and GTA4. In San Andreas, I often found myself spending boring amounts of time on the highways between each of the THREE cities. It was then I learned that I would've preferred just one densely-packed city full of stuff to do instead of three smaller cities spread out on a big map.
Likewise, I've heard that the New Vegas world map is going to be about as big as the FO3 Capitol Wasteland map was - and I'm okay with this. There are plenty more quests to do in New Vegas and that's all I really care about. Yes, there is such thing as "too small", but FO3 definately wasn't and nor will New Vegas be if it's "only" as big as FO3 was.