The Funky Gerbil.
That dazling dance of death that someone does when you set them on fire. In the originals, people would stop attacking and run and flail their arms and sometimes would run all the way across the screen. Fire in FO3 and NV is no fun at all. If I ever get my modding skills to the point that I can do animations I WILL bring back the Funky Gerbil.

More to do with the BoS. I thought they were pretty minor in the game. I know their role in the game was supposed to be minor but they could have at least had a few more quests thrown their way after you join them. Perhaps an expedition of some sort to a location in the game to get some awesome tech. Perhaps even helping them take Helios 1 back.

Black Isle anyone? ...just kidding

yes. lol.

New Reno. I was expecting more floozies and booze! If this ends up as part of a DLC I might just die happy.
Basically all the mature content that was in Fallout 2.
Hitmen chasing after your character the way Talon Company/Regulators would