Would the Federation have put into place a contingency plan to use the Omega Molecule in and around Cardassian space? A last ditch effort to contain the Dominion to Cardassia. Or instead of mining the Federation side of the wormhole have an unmanned ship fly through the wormhole and detonate a few Omega molecules on the Dominion end.
The damage done to subspace would make the wormhole useless for either the Dominion or the Federation since warp drive would no longer work for light years around the Dominion side. Make a big enough explosion and it would take the Dominion years, decades, a century or more to get through the damaged area to reach the Wormhole.
Doing the same thing around Cardassia Prime, and any other worlds the Dominion is using would also basically stop the Dominion and Cardassian fleets. It would cut them off from the rest of the AQ. It would end the war.
It would be, to say the least, a "Scorched Earth" policy. But would it work?
For argument's sake, let's agree that the Federation can create and for a minute or two, keep stable an Omega Molecule.