Just as an aside, "the people who made it say it's so" shouldn't count as an argument one way or another.
If what they made looks like X, then it's X, and the makers have succeeded in making it X. If it looks like Y, it's Y, and those folks have failed in their quest of making it X. It's quite analogous to TPTB saying something like "First we wanted to have Scotty be clumsy and comical, but then we decided he should be sexy and menacing, so now he's sexy and menacing". Well, we're the only valid judges of that; TPTB have no say in it.
As for hatch measurements and the like, yeah, it seems clear that basically every detail that so vividly reminds us of the ST:TMP ship is actually something completely different in terms of function and scale (windows instead of viewscreens, chutes instead of doorways etc.). Which is weird in in-universe terms, and suggests incredibly lazy artists in out-universe terms (even though the real reason is they weren't given the opportunity to get busy with a proper re-scaling), but there we have it.