I woudn't call Fallout 2 a black sheep, if anything it tried too much to not be a blacksheep, to please what was the most likely large audience at the time. My vision is that Fallout 1 is the black sheep, because it's the best and the only one that really had Tim Cain.
I am not saying the 2 is bad, it's a good game for most and even has some great. I sometimes wonder what it would have been if it's development had been similar to the original. Meaning left alone, not bringing so many new people in, not rushed, and not forced to be 'bigger' in worldmap and so forth.
Vegas, some bad gameplay stuffs left aside, actually did very good at recreating the better sides of Fallout 2, the serious lore and tones that is, and expand with it, make it evolve, so it definitly show that the 2 is good. But hearing that NV was made by the people who made Fallout, well it's not really true so it itch sometimes.
However the 2 tend to be credited for things that already exist in Fallout 1, like the restart of civilisation, and the people trying to figure how to move on. It's just less obvious and not the central theme most of the time, except with the followers of the apocalypse, and the unity actually. But it is already there, and other locations show it, like Shady Sands, Junkyard, the Hub, even the Brotherhood in their own way.
Still I used to not mind the worst sides of Fallout 2, until it appeared later that they are the most standing out elements in the mind of people like bethesda, and what made the game so known.
The vault tech experiment grew all over the place when it was just a vague idea in Cain's mind to begin with, and who know if he would have keep it? So many damn vaults and their supposed 'useful' experiments in New Vegas for example, on a area that is not supposed to be so large and it look like I didn't even run into them all. And let's not (or I) go into the 'Yeah, america fucking US, baby' phenomenon that bethesda seem to love.
