I always liked that DS9 was willing to take chances and do things that are unexpected. At the beginning of the episode I was fairly certain they'd stop the Dominion from taking down the minefield either by sabotage or the fleet breaking through.
Well surprise both the saboteurs and Defiant were too slow! Sure it's a convenient handwave solution, but it's one that was surprising and it worked. It's not as if this came completely out of the blue and it's perfectly feasible that they have "godlike" power in the wormhole they constructed for themselves to live in.
Things like this were really why DS9 was my favorite series. They'd go out on a limb and do something against the grain or unexpected. Actually my biggest gripe with the episode was why did the Klingon fleet not go directly at DS9 itself? The Federation fleet had the Dominion/Cardassian forces tied down and the stakes were clearly outlined as victory or else death. Personally I thought it'd be very in character for Gowron to have the Klingon forces take all the glory and let the Federation take it on the chin.