More fairly, 3 stars... But 2 captures the disappointment involved in watching Cronenberg get boring. Really, though, it was fine, in the sense of being mediocre, straightforward, banal, passable. Nothing overtly *wrong* with it (except the wasted opportunity, and maybe Knightley's acting)... It's just not very good.
Hard to believe a story about academic dispute between three major figures of a whole century, would fall pretty much the same if names and backgrounds had been left out completely. What we get is a carefully crafted context plus few names and years, just wrap it all in a plain love drama with some shy S&M and disappointingly prosaic dialogues.
This movie is great just to see Michael Fassbender and Viggo Mortenson trade blows as Carl Jung and Sigmund Freud respectively. Also Keira Knightley is exceptional in this and the bondage sends between her and Fassbinder are great too. Very talky, but it's some good talk.