That's weird. I always felt like the Picard/Minos Korva connection was understated in the episode, in fact, the original script had them talk slightly more about it. It does feel to me like it's a solid piece of the puzzle, because they DO plan to attack it, if Starfleet doesn't bend at the negotiating table. Having that info for how it's to be defended would be useful. Possibly it might not be as advantageous as the nebula fleet, that no one knows about, but still... It's another pin on the board that could be a factor in them getting it back somehow. I get the impression that they only back off it, once they realize Picard has been kept in the dark. It's a dead end & they probably figured it outBut that means they didn't really need Picard in the first place. If they don't need the defense plans for Minos Korva, then they only need the casus belli, and any random Cassus or Billy can be trapped for that.
That is, they certainly did not win anything by removing Picard from the E-D; Starfleet readily sent the next fellah, who proved tough enough a nut. I seriously doubt Picard had better specific skills for defending Minos Korva specifically than Jellico or some other random skipper did.
The remaining question here is, how important was Minos Korva in the end? That is, is there a real connection in that the trap was tailored to capture the man currently tasked to defend Minos Korva? Or would it simply be natural for the trap to be tailored to lure in somebody from a ship operating in the general Cardassian front, which wholly incidentally includes the intended breaching point Minos Korva? I suspect Picard and the audience here jump to conclusions about the importance of the Picard/Minos Korva connection...
Timo Saloniemi
As to why they want it back so badly, who knows. Suffice to say, it's one of those border worlds that Jellico barks about them not being able to take by force, but want to bully back at the negotiation