^Who knows, maybe the idea of the new Enterprise being a half finished mess in STV was a holdover from that idea? I would certainly make more sense IMO. I mean the Excelsior is still a prototype, with all the inherent teething problems that implies while you have to assume SF had gotten pretty good at building Connies by that point, no? Plus as we saw, a ship in desperate need of attention is Scotty's idea of paradise!
Also, didn't some of the bridge display graphics for the new bridge mention transwarp drive somewhere? My memory is a little fuzzy.
As an added bonus I do remember that neither the STIV or later versions of the E-A's plaque specified that it was a Connie.