Admittedly there are apparently a couple of different Van Burens, started and scrapped over the course of the concept's life, and the design docs we have cover at least two (New Canaan / Jericho cover two at once). Still. The first rough concept, by Tim Cain and co., is probably closest to a Wasteland sort of thing - Presper (or whatever his name is) is a pre-war scientist woken from cryosleep who decides to wipe the planet clean. That's the sort of high concept sci-fi that can be worked into a WL framework.
But yes, the general sense that you get, reading the documents, is that while Fallouts 1/2 generally picked from classic Roger Corman "ray guns and giant ants" sci-fi for its creative anachronism, Avellone and Sawyer's VB emit more of a 60's / 70's cold war vibe, particularly in the Denver, Reservation, Nursery, and Boulder concepts (the Limit 115 virus in particular is heavily reminiscent of The Andromeda Strain / The Omega Man or even The Stand, though as I understand it that wasn't necessarily something that was definitely making it into the game). The setting also shifts from the post-post-apocalypse of Fallout 2, in which nascent societies like NCR and Vault City are rising and starting to resemble pre-war communities, to... well, a post-post-post apocalypse in which all of those societies collapsed and communities are on the brink (or about to dirty bomb everyone else and take over, in the Reservation's case). As of the end of the game the most powerful faction in the wastes is most likely Caesar's Legion, only occasionally encountered in forward camps and the margins of the map. That's not a promising future.
I spent a good year or two trying to pull as much of what was out there about VB together as I could for a pen and paper campaign back in the mid-'00s. Even managed to pick Sawyer and Avellone's brains about it, the former quite extensively, before Obsidian got the chance to work on the license again and both became relatively unreachable. Avellone in particular didn't remember a ton about it (though he does have design docs that aren't public, as evidenced by some talks he's given). But the sense that I got was that, if nothing else, they were distancing themselves from the way that Fallout 2 played out its humor. Everything I read was subdued. But that isn't to say that there wouldn't have been comical companions or dialogue. It's just that none of that came out of the stories in the docs.
