I'd love to see some brotherhood of steel DLC.
I know Sarah Lyons was supposedly "killed" but I personally believe she faked her and her supporters deaths to avoid being killed by Maxsons supporters, I would love to see her regain her position as Elder to the Capital Wasteland Brotherhood of Steel and declare Maxson as a Renegade. or have her Start her own "outcasts" to gain control of the Prydwen and try to regain her position as elder.
this would be the best outcome i'd like to see.
Though personally I'd have to say the Brotherhood is my favorite fallout faction, just because they hooked me in 3, had a bit of a rude awakening when I played Fallout 1-2-Tactics. I'd love to see some Brotherhood oriented DLC that would either retcon the current line, or deliver a delicious twist.
someone mentioned earlier in the forums about the enclave, and how Maxson would have recruited some of the survivors, maybe something like a coup would stir things up, or a Lyons Pride resurgance, if you went with the brotherhood ending they'd come and fight the prydwen brotherhood, and if you went with any other, the pride would salvage what they could of the survivors and equipment to bring order to the commonwealth or something, I dunno I'm only a good enough writer to get some basic plot down. and I don't want to waste words in this part of the forums.