For all the problems of NuTrek, Spock showing emotion is not one of them. Spock is one of the few things that works about NuTrek.
I don't know. In TOS seeing Spock be emotionless was one of the things that made the character, well, fascinating. It's his defining trait which seems to be ignored.
Yes, there are canonical precedents to explain this, and indeed we did see him in his younger days of the Prime Universe prone to grinning and shouting outbursts. But if I were to present TOS to a new audience, emotionless Spock would be the representation of the character I would present as I feel that is more interesting a character to watch and learn about then someone who is "young and emotionally raw" the Abrams series depicts.