Since FO:NV is probably going to look exactly the same as FO3, but have better characters & writing, the game is only going to svck if Obsidian manages again to not finish the game in time (KOTOR 2, NWN 2, Alpha Protocol). But since Bethesda is not a tirannical publisher (for instance, without Bethesda Call of Cthulhu would never have been developed, let alone released) this shouldn't be a problem.
KOTOR 2 was the only game pushed out unfinished, thanks to LucasArts. NWN2 just wasn't great, especially the ending, but then again, FO3's original ending was pretty lame, too. Didn't stop the game from being successful, so I guess endings are overrated. Heh.
Bethesda's gotten much better in recent years, though I still haven't forgiven them for Daggerfall. Now there was a buggy, unfinished mess.