I only recently purchased this game when I happened to find it on sale and so far I'm really enjoying it. I've played the 2 player variant a few times now and it's an incredibly solid 2 player game. Using a 3rd neutral colour for placing workers to use during the movement phase works really well and does not seem to increase any fiddliness. As the game progresses and players get more tribe markers, using them to move the neutral workers becomes one of the more competitive aspects.
Overall a surprisingly well developed 2 player variant, given that this was designed after the game was released. If it was ever reprinted I think it would be completely legitimate to include the 2 player rules and label the player count as 2-5 rather than 3-5.