I think gay representation in film is very important theme and it's great this film is created a discussion about it.
Some years ago a movie like TIG would be considered daring nowadays that it's very common, at least on cable TV, to show explicit scenes when the main characters are gay people are talking if the movie needed them.
There's a long tradition in no showing romantic gay scenes but in the other hand the excuse about the structure of the film has some logic
Also I found interesting how a good number of people in the gay community seem to enjoy the film. Even some commenter and leaders defended it:
The human rights activist Peter Tatchell said this aspect of “a brilliant, moving film” did not worry him. “Although the absence of any depiction of Turing’s gay life is disappointing to modern eyes, it is perhaps an appropriate symbolic reflection of his secretive attitude towards his own homosexuality and of the sexually repressed atmosphere at the time.”
http://www.theguardian.com/film/2014/nov/14/alan-turing-name-restored-the-imitation-game-film
http://www.telegraph.co.uk/culture/film/11230676/The-Imitation-Game-Homophobia-is-still-with-us-60-years-after-the-death-of-Alan-Turing.html
http://www.theguardian.com/film/filmblog/2014/oct/09/the-imitation-game-alan-turing-gay
I recently read a review of this movie by an American critic and he said something really disturbing. He said that the movie was very good but it didn't dwell enough about his homosexuality and it was clear because it was rated PG-13. Criticizing it because it didn't show enough romantic scenes between two men is valid but citing the rating is just stupid. There's nothing bad with a PG-13 movie with a gay hero in the center of it. Actually it's great if Weinstein is thinking in school trips to go to see this film (by the way, in 1993 he famously did a very successful Oscar campaign based in a gay sex scene for a small Irish film called The Crying Game). I'm sure there will be more daring, complex and better films about Turing but I'm not sure they will have the scope of this movie so I'm happy with its success. And we will know things have changed not when we see a gay film with explicit content win the Oscar but when we have gay movies for all family.