In an ideal world, he would have quickly crushed the Federation and used the minefield as leverage against the Dominion. But that was never likely to happen, as Cardassia needed the Dominion forces to defeat the Federation and Klingons, who weren't going to roll over. They also need plentiful Jem'Hadar to occupy and pacify their conquests to prevent future resistance.
The more you think about it, the more ludicrous his plan becomes. It could only end in two ways, neither of them good for him. Either the complete subsumption of Cardassia into the Dominion, or the defeat of Cardassia by the Allied forces. If the minefield comes down, Cardassia becomes just a minor part of the Dominion supremacy in the Alpha and near-Beta Quadrants. If it doesn't, then victory becomes a lot less likely, and it becomes a lot more difficult to hold on to the worlds they manage to capture.