I'm still working my way through the game, but so far I kind of agree with the OP, and I'm definitely not seeing this "OMG SO MUCH BETTER THAN FO3" thing that some reviewers are gushing about. First, they say it's funnier, but so far the only funny thing I've ran into was the crazy guy in Novac. Most of the rest of the game has been ultraviolent massacres by Caesar's Legion, doom and gloom, and people complaining incessantly about how they hate the gub'mint. It seems way darker than FO3. FO3's opening was funnier to me at least; I thought the GOAT was really clever, and the whole birthday party and tunnel rats thing was light hearted; and the first town, Megaton, had Moira who was funny. I've been so far to Goodsprings, Primm, Nipton, Novac, Mojave Outpost, Ranger Outpost Charlie, that mining town up north, and a few other places, and I haven't seen any of the humor.
Then the quests... I don't have many quests, and the ones I've done have often been really short. As for more locations, in FO3 I always felt like there was something to explore... there were "dungeons" all over with the sewer system and subway tunnels, but most of the places I've randomly went to in NV have been empty with nothing to do. I guess the big cross monument, the racetrack, and a few random shacks are interesting to look at, but they're empty with nothing to go into, nothing to fight, no items, no NPC's, nothing. I think that's one thing I really miss from FO3, is that they designed a lot of the places as "dungeons", with monsters to fight and treasures to find, and big winding corridors to explore. Most of the places in NV are just tiny empty shacks with nothing in them, or landmarks that you can look at but serve no gameplay purpose. I guess that's more realistic, but I'm not really playing for realism, I'm playing for fun.