Well, if we have such an active thread I would like to insert my comment too (and ensure I posted on a forum at least once, he-he). Though I generally not very fond of the way naossano is bringing up problems, I can't deny their existence. There are faction number issues, but I don't believe they could be fixed during current session effectively.
Personally I got to V-Tec because of two reasons: the faction recruiter was easy to find and vault is kick-ass. I never had an alt and I really don't wish to have one while free rerolls are around and I'm satisfied with my current faction. We have all kinds of people, some I like more, some less, but in general they compose a team I love to be a part of. Nevertheless I have my mind set on switching faction after the wipe to one of the new ones if there will be any.
Speaking of development, I like Lidae's way of thinking. A tech progression in factions would be nice and possibility for players to contribute to it by ZC, assignments, dungeon completion and other possible ways would be great ("Lads, take your piperifles and bring me dat computer from RobCo!").
About factions: in my opinion there are three general things considered kick-ass by average fallout fan: vaults, Brotherhood of Steel and Enclave. So the presense of faction with "vault" in name is a sort of mistake. Maybe it could be made a sort of locked faction you could only enter having achieved some serious success in initial faction? Though there should be probably two such factions for balance reasons alongside four or more usual factions.
That leads me to the thought that some in-faction platoon, fame, reputation and trade tweaks should be made to inflict a harder progression on players.
Sorry for my mind-flow style, but I got a number of thoughts and just had a wish to share them I could not overcome