Apologies if this has been mentioned before -- I did a search but found no mention of it. Here we go. Based on the description of the 9-minute preview, I believe a key clue involves the girl's debilitating disease. She isn't simply sick. She has hyper-aging, something like Hutchinson–Gilford syndrome (a.k.a., progeria syndrome). The descriptions say that she looks old. Thin grey hair and all. "Harrison" comes and says that he can help the girl. He can save her. Benedict Cumberbatch's character doesn't have magical, all-powerful healing powers. He has reverse-aging powers or technology. Remember when Noel Clarke said that he wasn't sure we was in the movie? Clearly the hospital scene can't be a major plot point, merely a clue to what happens later, like the various openning scenes in ST09, many of which were cut from the finished film. Various people have speculated that Benedict Cumberbatch could be playing Garth or Robert April (based on production sketch seen on the press tour), but isn't Cumberbatch too young to play Garth or April? Or isn't Cumberbatch fairly young in general for someone who is returning in long-festering vengeance? I think Cumberbatch's character has reverse-aging powers or technology, and he adopts a pseudonym -- John Harrison -- to hide that he is a decades-younger April or Garth or whoever. If April, as some think, this could be a clever homage to TAS's "The Counter-clock Incident," but others would moan that it also evokes "Insurrection." Even crazier idea: What if Peter Weller is old Cumberbatch? We see him when old and wronged as Weller, and he returns having reversed-aged into Cumberbatch. Maybe not. But I'm thinking reverse-aging or rejuvenation is involved in the girl's disease and Cumberbatch's identity. The disease at the very start of the film, which could easily be cut according to one of the actors, is a clue that sets-up who Cumberbatch is: he has reversed-aged somehow.
Here's one of the relevant descriptions of the girl's condition: http://uk.ign.com/articles/2012/12/10/weve-seen-the-star-trek-into-darkness-imax-footage And another: http://www.hitfix.com/motion-captur...-darkness-teases-expertly-and-answers-nothing
I don't think Weller is old Harrison, if only because BC is old enough they would just do aging makeup — Weller looks too different to bother casting that separately.
I think it's one of the more reasonable theories I've heard. Dunno about Weller being older Cumbercatch, but it's an interesting premise.
Yeah, I'm not wedded to the idea of Weller being older Cumbercatch. Like I said, that's perhaps a bit too outlandish. The rest, though, I'm sticking with (for now) as my prediction.