Sisko is more liable to go crazy at any moment, he gets his hands dirty with his crew.
Picard generally let Riker deal with the disciplinary issues, Riker his Picard's "muscle"
Sisko didn't have a real first officer like Picard had, well he had Kira but she was her own woman and worked "alongside" rather than "with" or "for" Sisko. And Jadzia wasn't the one to deal with that kind of thing.
The dynamic aboard enterprise was different, notice in First Contact Riker had to be not on the bridge when Worf kicked off because otherwise the writers would have had to have him do something.
Notice the symbolism a lot of Riker standing just behind picard, staring. Also note that while Picard is a small, older man Riker is a lot younger and a big brutish looking man.
He's his henchman
I really like this analysis! I think it becomes less true as the show goes on, but you're right, Kira does not work "for" Sisko in the same way Riker worked for Picard. Riker and Picard definitely were a "yin-and-yang" combo in a way that Sisko and Kira never were.
R. Star wrote:
Of course the possibility exists that Dax, who's known for her mischievous nature, did just make that up to yank Sisko's chain.
Haha, this seems very plausible to me.
I think the whole Q thing is more a symptom than a cause. I doubt Worf heard about Sisko punching Q through the grapevine 3-and-a-half years after it happened and then, all of a sudden, said, "Hmm. Captain Sisko intimidates me." (Nor do I think the story would've spread across the fleet.)