I wanted to ask and confirm something. Wasn't the Dominion planning on invading the Federation before the discovery of the wormhole? It's been years since I watched DS9 through completion. I recall that the Founders had the intention to invade the Alpha and Beta Quads prior to making contact with Sisko and co. The Bajoran wormhole only accelerated their plans. I do remember the Jem'Hadar being exicted about fighting Klingons and even knew about their signature weapon the bat'leth despite first contact being made prior to the Dominion traversing the wormhole. With how easy the Dominion took out a Galaxy class and how resistant it's ships were to type X phasers. It could be plausible the Dominion had been planning this war for decades if not centuries beforehand.
I believe it was Wolfe who mentioned that in the DVD interviews, but it never was made explicit in the series that was the actual case. Still, an organization as large as the Federation would have drawn the attention of the Dominion at some point due to subspace communications or exploratory probes. The Feds would have at least been able to star chart the area near the wormhole for Sisko to identify the nearby star when he and Dax first go through.