You know, I don't think it is out of the question. We've played it a few times with two and there are a few things that don't work as well, but it is still fun. I think I could come up with a pretty good variant for two players.
The reason why I've listed it for 3-5 for the moment is because the trading doesn't work so well with two. But I'm pretty sure it could work with a rule variant.
Has the game been adjusted so that it works well with 2 players now? Both BGG and Kickstarter lists it for 2-4 players... as all my gaming is on 2 players, this is one of my main factors in whether I would be wanting to support a game like this or not.