You see this a lot.
"Oh this should have been a FO3 DLC. It's just the same textures but with more quests, more weapons and armor, Locations and more faction."
However in my mind, how does New Quests + New Weapons + New Armor + New Locations + New Factions =/= New Game?
These "The graphics are the same" arguements never hold much water. They usually just come off as bored and moody gripe fests because they didn't overhaul the graphics engine but, god forbid, spent a lot of time and money working on far more game-oriented features.
It does seem that some seem to be under the impression that for the game to be considered a new game, it has to completely overhaul the graphics, and many other aspects of it, completely failing to consider that New Vegas is hardly unique in reusing many assets in a new game, in fact, Fallout 2 did this as well, and at least New Vegas is considerite enough to not market itself as a full sequel, as I've said before, New Vegas is, to Fallout 3, probably closer to what GTA: Vice City or San Andreas were to GTA 3, so I didn't really expect it to completely overhaul every aspect of the look and feel of the game, Bethesda is probably going to save that for Fallout 4, which New Vegas never claimed to be.
But yes, considering that Obsidian decided not to completely overhaul the graphics, what they're doing to make the game distinct from Fallout 3 has so far impressed me, I mean, sure, I can easily tell where it reused things from Fallout 3, but it still seems to me that Obsidian is using what they have to work with to pretty good effect, and in any case, I'm just glad they're going for a somewhat different feel from Fallout 3's wasteland. Not that I didn't like the wasteland, but looking at all that brown got a little boring after a while, especially when so many modern games take that direction even without the post apocalyptic setting, so a break from that will be welcome.