I liked New Vegas a lot more mostly for why I play role playing games: a sense of cohesion and value between choices and consequences. Bethesda, in my opinion, fucking suck at doing this. Oblivion, Skyrim, and Fallout 3 all suffer from the same problem where every choice you make is largely inconsequential and meaningless. And when I say "choice" I mean it in the grandest scope possible: from how you tailor your character's stats, the dialogue choices you make, and where you go in the game world.
With Bethesda's games I feel like I'm playing a pretty free form and relaxed sandbox game with a stat system bolted on. One very forgiving for any of the choices I might make or the things I might do. It's a streamlined experience that panders to playing through with one character for 100+ hours, seeing and doing mostly everything with one "life".
This, for me, is at direct odds with the roots of what defines "role playing", and where older CRPGs like Fallout and Arcanum shine. It's also where Obsidian really excel more than anywhere: a strong sense of responsive game design to the decisions you make. With Vegas the game world felt a lot deeper and versatile to the kind of character builds I could make, and the way I played those builds in the world. Where I could make a choice in a quest, wear a certain outfit, and behave a certain way, and the game world would respond to my decisions. That's a really big, important aspect of role playing to me: I need to feel the game world is organic and responding to my decisions, to make the character I'm "role playing" as feel even more unique and integral to the game world.
Bethesda does excellent world building, I just find the act of playing them a bit tiring and dull. I start off excited and interested in digging deep into the world. Then 20 hours later I feel like I've seen and said it all. New Vegas had far more interesting, morally ambiguous characters to engage with, more varied and investigative quest trees, and mechanics that favoured role playing over wayward adventuring. New Vegas is what I wanted from Fallout 3, basically. I don't think it's perfect, but I did feel Obsidian did a far better job of crafting a proper successor to Fallout 2, both in lore and design, than Bethesda did.