Again, the discussion keeps veering into structure, and honestly, I don't care much about structure. Of course, you can't have a good story without good structure, but having good structure doesn't guarantee a good story. It's a foundation. And yes, I agree, all of these games have very solid structure. That's undeniable. But what I'm more interested in is themes, tone, aesthetic, etc. The more ephemeral aspects of storytelling.
FO1 had something to say, and it said it. Even if it was unfinished and in some places janky, it had a clear point it was driving towards. It was a finished, holistic work. The sequels, on the other hand, are like addendums. They may be structurally or mechanically good, but they're nothing but re-iterations of the same themes, and as such, not as powerful.
It's far more interesting to experience the story OF a universe, than a story IN a universe. This is the problem with all great works that become franchises. The first work delivers a message or theme that the universe is ABOUT, while the subsequent works tell stories WITHIN that universe. The stories themselves might be well crafted, but the most important aspect was the "message", and that was told already in the first work, so the sequels are artistically pointless.
It would be like writing another Lord of The Rings Book after Sauron is already defeated and the ring destroyed. Sure, the story might be good in itself, but what's the point? The story of Lord of The Rings IS the story of The Ring and Sauron, and what they represent: how Evil eventually destroys itself. Without that, any subsequent story is just "things that happen". I don't care about things that happen, I care what the things that happen are ABOUT. You get me?
This holds true for many video game series, for me. Half-Life 1 was better than Half-Life 2. Diablo 1 was a more powerful experience than Diablo 2. Fallout 1 was a more powerful and self contained work than FO2 or NV (let's just not mention FO3, ok).
I could elaborate on these other games, but let's focus on the Fallout series. The theme of the game was "War never changes". What is meat by this vague sentence is that civilization is inherently barbaric and ultimately self destructive, and all attempts to "resurrect" civilization after it destroys itself amounts nothing to nothing but treading through the same path, and will also ultimately result in self destruction. That was the point of The Master and Unity. An attempt at rebuilding that was ultimately futile and "stillborn" (literally). Making the supermutants infertile (while The Master, a superintelligence, didn't catch this obvious flaw) is a hamfisted move, but ultimately works towards delivering this central point, so it is forgivable. Fallout 1 presents this bleak setting of disconnected, almost tribal societies, scrapping by in a hostile environment that prevents the rise of any kind of organized civilization, but it also kind of revels in it. You get this sense that this world without civilization or large scale organization is somehow "right". Almost in a kind of anarcho-primitivist way. And attempts to rebuild civilization are portrayed as inherently flawed and evil. I think it's a powerful message.
FO2, on the other hand, just re-treads the same message, this time with the Enclave (remnants of the Old World trying to rebuild itself, even more hamfisted and obvious) as the "civilization builders". And it's not hard to see why: FO2 was merely an excuse to iron out the gameplay flaws of the first game, add more content, and the story was sort of tacked on to "glue" together the content. And this is the kind of thing that happens with all franchises. The first game has a message to deliver, but the subsequent games are just excuses to deliver better gameplay while telling essentially the same story.
And I'm a gameplay guy, don't get me wrong. But I think that gameplay has to have some context to prop it up. And if the context is weak, the game is weak. I don't want "more of the same". I just want more. Of different things. And if FO2 was a derivative of FO1, NV is a derivative of a derivative. The central themes of what makes Fallout "Fallout" are almost entirely gone. The Hoover Dam debacle is now far removed from the idea that Civilization Is Bad(tm), it merely tells a small story of a bunch of Bad Civilizations during their power struggles. It's a Story In a Universe rather than a Story About a Universe. You get me? It's equivalent of a book describing a war in the Lord of The Rings setting after the ring is destroyed, between the good guys and the easterlings. No matter how good the story is structured, it is pointless, because the "point" of the story was already told in the first trilogy.
I don't think that NV is a bad game, ultimately. I think it's good. But I also think that it's overrated in that people in the CRPG community think that "choices" equals to "meaning". You can have a game with no choices that delivers a powerful message, and a game with many choices that ultimately lead to nothing.
I think the biggest folly of the CRPG genre is 1) trying to imitate pen and paper RPGs for their superficial aspects, and 2) mistaking what really makes PnP RPGs interesting (hint: not the story). The story of an average PnP RPG session is an incoherent mess of ad libs and retarded player decisions. You can't make a good story out of a PnP campaign. What's interesting about them is the dynamism and interactivity. Because the "game engine" is an actual human being. But games can never get close to the versatility offered by a human GM, so I don't think they should even try. Trying to do so only leads to boring outcomes like trying to fake "choices" by having the same pool of quests and missions that you can go through in different orders, when the pool of quests stays the same. I think games should go in a different direction altogether. Something more generative, perhaps, like Dwarf Fortress. Where there's no authored story. Where the gameplay IS the story.