Establish a vision and go with it. The Fallout games are great, but to progress the series, you need to separate the wheat from the chaff and build on top of that. Refine the strengths of the Fallout games and add new innovations. There's a lot of dissonant noise from fans about what those strengths really are. And that's fine. It's not their job to make the game. They aren't a team. But you have to be able to get to the heart of what's really important.
There are probably a lot of decisions that you will make that infuriate a lot of people. If you feel those decisions need to be made, do not half-ass them. The people still will be infuriated, and what you are making will suffer overall because of those compromises. A compromise made for reasons of scope or quality — that might be a good compromise. Compromises made to quasi-please the average audience member aren't a good thing, especially not with a concept as strongly expressed as "Fallout".
And whatever you do, make sure you nail the art, the music, and the sound. That's the stuff that transcends rules and combat systems and dialogue trees.