I'd love to see Obsidian do another West Coast themed FO after FO4. Though, I think Beth allowed them to do NV as a nod and throwing a bone their way, so Bethesda will probably not allow it...as they seem to not even acknowledge it exists in public statements.
Anyhoo, there was more great stuff brought into the FO universe's first person generation with NV, and I preferred it over FO3. Better story and companions, excellent DLCs that told their own story, more weapon types, weapon mods, ammo types, reloading, survival crafting with healing over time, crafting interfaces, more explosives and explosives crafting, hardcoe mode, a gun industry that manufactured weapons from old world schematics, Caravan, and more varied armor types to include Riot Gear and breathing masks.
I'm in the middle of another run through as we speak. Just don't think Bethesda will allow them to do it again...even though it's money in the bag. They own it now, for good or for ill and probably don't like competing visions within the franchise vying for supremacy.
But...I hope they have the long vision in mind, and realize that it's almost a freebie FO game to publish while they work on ES6.