I don't see NV frankly being any different than 3 in literally any regard other than having a more competent storyline. Shit was 1:1 copy paste job mechanically as far as I'm concerned with better writing.
Disagree, I never felt I could role play in 3 and when I replayed it (when I really judge a wrpg based on past experience and playthrough) and it was the same experience. It was constricted, felt like nothing new. The options were goodie two shoes and illogical evil psychopath. When I replayed NV, I did things totally different in a completely different manner without it coming off as cheesy and could role play it and craft a story behind my character and stick to that. I can't do that in 3, you're the kid of a scienctist dude in the vault who is trying to save the wastes. Why would you blow up megaton if that's the case? And it's not like you can change your destiny with your father either. New Vegas, despite giving you a backstory later in the game allows you from the beginning to curate a personality and play style. 3's choices are completely limited by comparison. I think a lot of people like to play those games and go boom boom everywhere they go. I tend to play science and communication characters and sometimes low intelligence characters. Despite that, my options in 3 were always limited. In NV, they expanded triple. In Fallout I have always liked to play slime ball characters who mostly do the right thing within their own compass. Who try to survive no matter what without becoming insane or a door mat. A pragmatist with a good heart who survives no matter the costs. The person you could trust, but shouldn't really trust, but not fully neutral either.
I can do that in NV. I cannot do that in 3
Further, 3 has no factions of anything like it. They have factions but they're mostly just random dudes that shoot at you. Despite having a bad rep with the Powder Gangers for instance, I could still infiltrate their ranks and be the scoundrel I like to play.
In NV, when you wake up, the only thing you know is you're a courier. In 3, you've got a family and a friend and all this shit that makes it hard to play my style.
If you think 3 and NV are the same I'm not sure you really explored NV at all.
That said, the thing about wrpgs is often you don't know how good the game actually is until you replay it.