I've got a buddy who never watched Star Trek once until a couple years ago.
Liked TNG. LOVED DS9.
It's true most people don't care about 2nd-age Trek anymore, but those that do would all universally love a DS9 movie. Heck, I bet if it were possible to get the actors and one or two of the original writers, I'd personally run a Kickstarter to fund it and I bet it'd succeed.
All the same people who will watch Star Trek: Renegades would donate.
I wouldn't like to see a return of Dukat though, I'd like to see a focus on some kind of post-war Dominion relations.