^Sisko said Worf probably wouldn't be offered a command after "Change of Heart." That doesn't mean it was impossible.
In any case, Crusher was a physician and would not have been offered command of a starship. Doctors could command medical ships, but nothing more than that. LaForge would certainly have been a possibility. OTOH, there's no reason to believe Starfleet would ever reassign Picard, nor is it out of the realm of possibility that Starfleet would have offered the ship to an outside captain after Picard retired.
Exactly. In the long run, I think Worf had a shot at the E-F? Still, I think they'd offer Rikar the command first. Perhaps Worf to the Titan.
The fact still remains, Worf learned from Picard and Sisko how to command a ship and crew.