Q is supposed to be taken seriously?
Given the tone of the Craig films, I would say yes.
Incidentally, regarding Q and Ms. M, I wonder if reintroducing them would mean the movies would give them larger parts than has been the norm. The past two movies have shown no real interest in bringing them in for a perfunctory scene, so if they're being reintroduced that might mean they'll have more role in the story.
Also, Harris is considerably more beautiful than past Moneypennys; Lois Maxwell and Samantha Bond were hardly unattractive, but compared to the supermodel-level love interests they always looked quite ordinary.