The differences between Fallout 2 and Fallout 4 are much more clear than from Fallout 3 and Fallout 4, even barring the perspective differences. And Fallout 2 was even a large departure from Fallout 1 in many ways. The point I would like to make is that these changes are inevitable when games change hands among developers. I don't see a problem with Bethesda's vision for Fallout, but there are things which I've enumerated above which I think could use some significant improvement.
It wouldn't hurt the series at all, and I don't see how anyone could argue that. It would help the series. Bethesda is adamant on a first-person/real-time gameplay, and I'm fine with that, but it couldn't hurt the series, and I think all players could appreciate better dialog, story, world reactivity, and player choices affecting the game-world.
lol, I'm an NMA guy too actually, but I don't hate Bethesda's games or even Fallout 4. I quite like their style, but it could use some work, which is the same for mostly any game or series. Even Fallout 1 could use some work, and Fallout 2 didn't improve some of the negative aspects of the first-game, but seemed to accentuate more of them, especially the poor-turn based combat, which could have used an over-haul in the second game, along with the poor AI. It may have been due to technological limitations, but then again, I think even SSI did it better.