If STID was true to the canon of realism of the previous films, a mentally deranged crew member would have fired the torpedoes, they would have reached Qo'noS in 3 seconds at half inpulse. The Klingons would have detected the Enterprise by picking GATT's positronic energy, forcing them to hide in the gravity well of a planetoid obscuring their warp signature. Kirk would have driven over the planetoid with a space buggy to the torpedo site to collect its quaternionic radiation in a test tube, which he would use to erase the deranged member from the timeline and stop the war, and Admiral Marcus would have been revealed to be a Klingon using the radiation to smooth his forehead, de-age and augment himself and Carol, who is shocked to find out she's a half-Klingon.
Oh, yeah, I almost forgot, the deranged crew member turns out to be an avatar of the AI behind Vengeance's self-operation, which is revealed to have the intelligence of a rebellious three-year old.