Spock swearing was funny because it had never happened before. He was still not quite fully recovered from fal-tor-pan, and was still relearning some of his "social game" (nearest phrase I can think of to explain it).
In the next couple of movies, Spock was recovered enough to look at a situation, and make the conclusion that it would be logical
to use a "colorful metaphor." Since he wasn't doing it all the time (or even more than once or twice), it was more effective.
NuSpock is already too emotional. Adding copious swearing would just turn him into an ill-mannered human with pointed ears.