I've had touches of grey in my beard since I was 25 (30 now), it happens to most of us at somepoint.
It's a shame that McCoy seems forced out of his proper place (love Karl Urban!). But it will be as much about trying to hit the right demographics and get more bums on seats than the characters place in the film.
Have to say I prefer AllStarEntprise
's version of the move poster (very nice work, btw).
Personally, I find Zoe Saldana to be very grating. I'm hoping she warms up in STID.