It also had some big gameplay departures from 1 & 2. I’m not talking about being an FPS (although no longer having to worry about accuracy was pretty significant) but the fact that putting on different clothing magically made you more intelligent, and that it was a lot easier to do everything.
In FO3 you can pick all the locks, hack all the computers, pass all the conversation checks, and take on hordes of enemies all by yourself. In FO1+2 you had to pick the couple of things you were good at and not be able to do the other things until your next run.