What's funny is, even though I left off the front views because I didn't have them all at hand, the Enterprise refit does fit through those doors, albeit barely... kind of like what we see in the famous scenes in TSFS.
When the doors are all the way open, the Enterprise has ample clearance on both sides. It's only during the hijacking that the clearance seems more narrow, but at that point the doors don't open all the way before Enterprise passes through them.
Interesting take... For clarity's sake, there is actually one feature that could be the same on the two... and those are the phaser banks. Scaled to 467 and 305 meters, their size matches somewhat closely. OTOH, there's no reason to think they really need to be the same size.
And at least one reason to think they wouldn't
: If Excelsior is being designed for a totally different role than the Enterprise, then those might be a totally new class of phaser weapons larger than anything ever mounted on a starship before. This might give you a less jarring progression towards the phaser strips on the Enterprise-C.