At this point, DS9 is an exciting playground of stories and characters, so the decision to focus this entire episode on just one of those stories and two of those characters was bizarre.
Yeah. The idea seems to have been that these two characters needed some quiet time with each other and a last adventure together. But... I don't think it needed to be in isolation at all. Even if they needed to use the main DS9 set, I think a more straight-forward story would have worked much better.
Just a misfire.
I agree about the first 15 minutes being very strong, in passing. They made a mistake by resorting to such a gimmick when it wasn't necessary at this point at all.
It seems to be a tendency that Trek writers have. I guess because the standard Trek episode has historically involved a tech gimmick of some kind fairly often.