^As long as it's part of the same novel continuity overseen by the same people, it wouldn't "just change." If anything, the novel editors and authors seem to have gone out of their way to embrace the notion of the difficulty of retrofitting ships with slipstream drive. The idea that it required a specific hull configuration was just a handwave I came up with to explain why Titan didn't get slipstream, but later novels have really run with it and made it a major plot point. So any change to that status quo wouldn't just happen, but would need to be justified in-story, like the way the Pact scientists deduced that Dominion tech could let them achieve it.
And this kind of attempt to make tech feel like tech instead of "magic" is greatly appreciated by many Trek fans. Myself to be certain. It can mean the difference between looking at a fairly improbable piece of tech and going, "Well okay it at least makes some sense with what's gone before." or looking at such a thing and wanting to throw things at the screen. *cough*microtransporter*cough*