Re: Kirk vs the Dominion
If the god-particle that is "red matter" was used on the Wormhole I suspect that the damage to subspace would be immense, probably enough to pervert any sort of warp travel along its course, not to mention it would kill millions on Bajor, its moons and the other planets, as well as DS9 itself. It's use would be too dangerous for anyone to even consider using, let alone actually deploy.
I don't know? When Vulcan was imploded it seemed to have no effect on Delta-Vega which was relatively close.
"I had no idea you were so... formidable. " - Anan 7 to James T. Kirk, A Taste of Armageddon