Thats something new.
What exactly you disliked in NV? It was far better than FO3, in my opinion.
No thats not something new, a large number of Fallout 3 (or whole series) fans disliked New Vegas and only bought it because it was a Fallout game. I am one them, I bought New Vegas including all dcls( call me stupid if you like) in hope they would improve the game and so I would not miss anything story wise.
New Vegas got good reviews from most magasins but read through fan reviews and several forums and you find a lot of dissapointed fans. The only thing New Vegas has improved on are the followers, the whole atmosphere(one of the things that made Fallout 3 so amazing) of the game svcks though imo.
It has quite a few fundamental flaws and only few good points. Starting with the main quest ... Whoever you side with whatever you do it will not affect the wasteland at all. All factions are pretty much evil/selfish and the legion just silly on top of that. The motive for the main character is revenge, to kill Benny and get more info on the platinum chip.Weak. There is zero sense of survival, most people have food,water and electricity in abundance and it is no problem getting filthy rich in no time for the player. The whole Mojave feels very empty, many houses are unused, plenty of effing invisible walls. When entering New Vegas 90% of all quests are run from A to B and talk to this and that guy. It is also divided into rather small sections btw. And the list goes on and on...
Dont get me started on game breaking bugs, but to be fair Fallout 3 had them as well in the beginning.
All in all New Vegas is a ok game to play through once or twice or even 3 or more times with mods but it doesnt come close to Fallout 3 sadly. I think if the "official" rewievers had more time to do their rewievs and see the big flaws of New Vegas, it would have gotten much much lower scores.