I like the notion that Sulu was promised Excelsior in TWOK. After more than a decade driving Kirk around and effectively being the second officer, the guy deserves it.
So yes, how about him being slated to take over Excelsior for her shakedown cruise, but the whole Genesis thing pushing that back. Styles was either the officer in charge of her construction, or more likely the guy they put in charge after Sulu was held up. Then, with the transwarp failures pushing everything back indefinitely, the recently-exonerated Sulu asks to be kept at his rank and position as helmsman so he can stay on the new Enterprise's shakedown. The whole God thing over with and the Excelsior project on the move again with a standard warp drive, Sulu happily slips into the white turtleneck for the job he was made for. Cue credits.