Likeness is not THAT important... acting skill is.
For example, take a look at the movie "Ike", where Tom Selleck (!) plays Eisenhower. He looks nothing like the real Ike, but after only 30 seconds in the movie, you have completely forgotten what the difference is. Selleck really makes you believe he IS Eisenhower; that's the power of good acting.
I'll wait until I've seen the movie before I judge Quinto or any of the other actors.