I'd be interested to know if this was JJ's idea or Paramount's. Wouldn't surprise me if the Star Wars Episode 7-9 announcement factored into this, the nine minutes being a way to recapture some lost thunder for Trek XII. Not to say that they needed to--I think Trek XII will be plenty high-profile when the time comes--but it does strike me as the kind of consideration a studio suit would tend to make, for good or ill.
Yes, the grand new announcement, what everyone wants to see!
STAR WARS VS STAR TREK
I wonder which fanbase that would piss off more?