Given how great the investment and attention to detail is for the prop used in the first movie, it seems completely implausible that something this big (the kink) or this nonsensical (the change of door type) would "have" to be done in the second movie. It's a choice made out of free will, in a movie where one can afford to burn things the old TV shows only dreamed of building.
You're again assuming that "attention to detail" and "attention to canon" are the same thing. It looks like a very detailed prop to me, based on what we can see, extremely well built.
But as I have been saying for years, JJ Abrams' production crew seem to be under the impression that they are trying to make a successful motion picture, as opposed to an internally consistent addition to Star Trek canon. If you asked the set designer about the differences between the two shuttles he would probably shrug and say "Yeah, I suppose so... why do you ask?"
If the second movie for some reason wanted to reproduce the smallest shuttles of the first one exactly, it would.
Right. I doubt they wanted to reproduce it "exactly," more likely "close enough" while still being functional for filming purposes. You know better than anyone that between films the sets and props can get completely re-detailed with no explanation whatsoever, nor even an
attempt at in-universe rationalization (take, for example, the changes between TMP and TWOK). Most of the time these changes have to do with the set designer's thinking or the production crew needing to do something with the props or the set and adding things here or there to make it look right.
But obviously that's not the motivation behind this prop, which is labeled as being from the 2250s or 2260s. Similarities with the 2230s design are probably there for the same reason both these designs resemble the old TOS design (and to the same degree): the movie needs the classic and iconic Star Trek shuttle, which can only be varied so much.
The variation isn't large enough that your general audience won't notice it's the same kind of shuttle that was used on the Kelvin in the previous film... assuming they're paying THAT much attention, and they probably won't.
Try to think of this from a filmmaker's point of view. The shuttlecraft is a piece of fictional technology: an aircraft, in other words. It has to look cool and it has to visually resemble a specific type of aircraft so that the viewers can tell any two of them apart when they're in the same scene, if not in the same frame. If this was something other than a Star Trek movie -- say, if this was a movie about an aircraft carrier during the Gulf War -- they would probably commission a few UH-60 blackhawks as the main helicopter for the big "assault landing scene." Now you and me, sitting here watching the movie with an eye for detail, notice that the UH-60 in the film appears to be a model that wasn't in service yet during the Gulf War. There are a lot of reasons we might speculate as to why this happened -- maybe they couldn't get a "classic" model for the film, or the one they wanted to use had a mechanical problem, or maybe they just didn't care.
The least likely reason is that they are INTENTIONALLY showing an advanced helicopter that wasn't in service during the Gulf War, to imply it's a different model or some sort of advanced prototype. From a production standpoint it doesn't really matter, as long as it looks good on camera.
So the notch, the gulwing door, slight change in the angles; doubtful these reflect any conscious deviation for in-universe technology changes. It's a lot more likely the changes were made when they finally got around to build the set, found out that a few things weren't working well from a production standpoint, and made changes accordingly. If anyone even noticed the differences between the set and the last movie's prop, I doubt it would have mattered.
