None of them are entirely bang on, which really is kind of the point.
A sort of holy grail, pie-in-the-sky, best hope for humanity scenario following the events of New Vegas would be something along the lines of an Independent (Courier-led) or House Vegas, that eventually forces both the NCR and Legion to come to the negotiating table and eventually co-mingles some of the values of all 3 states a few years down the line.
The NCR is pro-equality, pro-rights, and has the groundwork for what could be an actually functional democracy at some point in the future. Right now, however, the democracy that the NCR has, isn't what it claims to have. It's corrupt. Extremely. Basically a plutocracy with good PR. Also they're really slimy about expansion. That's got to go.
The Legion has the backbone and ethics that the NCR lacks - honestas, industria, prudentia - and the kind of work ethic that gets shit done. Not to confuse ethics with morality, by the way, that's something else entirely. Not to mention the fact that Caesar's point of The Right Kind of Government for the Right Circumstances, while harsh, is pretty much dead on. The wasteland is not a genteel enough place to allow a pre-war 'soft' democracy to succeed. It can be eventually, but it isn't there now. What the wastes need right now isn't a friendly gathering of equals, it needs a father figure to tell them to quit hitting your sister, do your homework, and eat your vegetables because if you don't so help me I will fucking spank you. Of course the downsides to the Legion as presented are manifold, and frankly pretty evident if you've played the game. It's too harsh in the social message it delivers, and as a society goes, it's unbalanced toward the military. Oh, and the whole sexism thing ... that's just wasteful. Caesar himself knew that the Legion had to change, but if/when he's defeated at Hoover Dam he risked losing his shot at it and it's not entirely clear if he had a backup plan.
In this scenario (crazy space aspirations aside) House/Vegas serve as the base to let this mixture work. It has what both the NCR and Legion lack: infrastructure and excess. Basically Vegas doesn't really need anything, and it has the ability to produce far more than it consumes. It's got water, it's got power, it's got technology, and it's got people. And most importantly, if things go right, it has all of this from a position where it cannot reasonably be taken by force. Assuming after the events of FNV, Vegas has the ability to secure territories within the borders of the Mojave, Vegas has an army of (or supplemented with) military robots, an orbital deathray, artillery emplacements, and an air force. It can make people play nice, and given the political situation, that's necessary.
