Something that Expands the Enclave Remnants, not the Enclave as a whole, but New vegas's Remnants being expanded and becoming a separate chapter to the ''Old'' Enclave,
A Better Legion, because i like being the bad-guy sometimes and new vegas didn't make that much of an option if i'm being honest, why not allow for bandit or evil tyrant like status in the wastes,being vilified wasn't the same for me...

I'd love to see a civilian faction expanded. I mean having a real and true experience in Freeside/North-West-East Vegas. Dealing with the kings, dealers... Or more quest with the Omerta, Chairmen or White Glove Society.

If not, I would love to see Shady Sands again, fully done, with quest, political choices, fighting against corruption or fighting for the government, having a full acces to California, annexing new territories... That kind of things.

Personally I wouldnt add anything new but change existing ones. For example I would expand followers, casinos at New Vegas to offer more quests with more interesting rewards. Also it always bugged me how Paladin Hardin speaks about how active BoS should be and he doesnt like the fact that McNamarra is passive, and when he is chosen as the elder he behaves much the same. I would love a mod that changes that.

outcast and enclave are my choices or a bigger BoS chapter that allows the player to end game with BoS while also progressing in the ranks.