The refit engine room suffers from what I call 'Brady Bunch Syndrome' - i.e., it's too big to fit inside where it's supposed to be even though it's supposed to fit in there, just like the Brady house.
Except it is not so much that it won't fit, it is that it is a tight fit. It works, but it is not the most logical layout. Of course, when performing a refit of an existing design, that is to be expected, at least once. The compromise is typically not a great solution, but it works. I have no problem with the existing fleet of Constitutions
receiving this refit, but I do have a problem with doing new-build to the refit spec. It would be akin to building "modernized" Essex class carriers from the keel up, rather than building a carrier designed for jets from the get-go. Not that the ships had outlived their usefulness, but if you were going to build a new ship, why build one with such an obvious engineering compromise if it is no more difficult to simply modify the design to incorporate the improved technology (I would envision a similar ship, but with some components moved around and a thicker neck - would resolve these issues, and be a more sound design - of course that leads us rapidly to the Excelsior design, because as you move back to the drawing board, you wind up changing "a little bit here" and "a little bit there" and the next thing you know you have doubled the mass of the design).