IGN has interviewed Lead Designer Emil Pagliarulo. The interview was apparently streamed live and was only accessible but subscribers. According to Zenmaster Omega at the Bethesda forums, Emil notes the following:
-the different people that can be recruited for your "party" will be limited based on your karma -"might" have some characters coming back, but they aren't talking about it yet -load times faster than Oblivion right now. -blowing up Megaton will make your karma "plummet" -There will be an invisible wall at the end of the world. -Brotherhood of Steel is a "neo-knightly organization that is waging war in DC" (direct quote) -Game is running on DX 9 right now and they would "never release just on Vista"
thinks it is very important about the original Fallout and Fallout 3
that all the factions, like Raiders, slavers and Super Mutants weren't
all completely evil and that you never knew where you'd find friends. -"Absolutely not" to multiplayer