Why was making Sisko a Commander "idiot thinking"?It's probably the same idiot thinking that made Sisko a Commander rather than a Captain.
At the beginning of DS9 he was being assigned to command a small station in an unimportant corner of the galaxy orbiting the 24th century version of a third-world nation. He had a crew about the size of the Engineering crew of the Enterprise, and his senior officers were Lieutenants, Junior Grade.
That totally sounds like a job for a Commander.