If the impact Voyager had compacted 5 decks like that, something similar must have happened with the saucer. And the work needed to rebuild THAT??
Voyager was in way worse shape, already having structural failure before an having an uncontrolled bellyflop. Data managed to glide the saucer in horizontally, and we saw that the front edge of the saucer section was undamaged after barreling through more than one hilltop. I'm willing to accept that the structure of the lower decks was largely intact.
The Ent D never would have gotten a new engineering hull if the Syracuse hadn't lost her saucer, presumably in the Dominion War. The restoration is a bit of a stretch but not as big of a one was as you presented, assuming I'm right about the lower saucer structure.

