I agree the "two class" system is most likely to be adopted. It's fairly simple, even for those who have no interest, and the only drawback is downgrading Pluto to "pluton" or "dwarf planet". But I guess everyone will get over that in due course.
Argos I'm not being negative, just realistic
Anyway, by the time mankind develops a suitable method of terrforming Venus, they'll be able to reach other planets that won't need terraforming, so the whole thing will be moot. Although I think it would be easier to terraform Mars.
haku While it's true that many things have been deemed impossible, only to become reality later, the problem with FTL flight is that it has been shown to be
mathematically impossible, which is a whole different thing. You would need a fundamental change in physics, or the discovery of a whole new branch of physics to bring it about. I'm not saying fast travel to other planets and solar systems is impossible, just that it's going to need something very different to get us there. In the meantime, we have to be looking at generation ships if we want to move to other worlds.