Sisko was great because it seemed like he was a Captain you could talk to (like in the episode "Adversary"). Picard didn't seem like a Captain that you can talk to so easily about things (if you were a lowly crew member). I mean, Picard had a hard time dealing with children even. I imagine Riker was the one who crew members went to if they needed some type of advice about something. Plus, Sisko was a very communicative father that spent time with Jake (whenever he had the chance). That type of attitude and perspective goes a long way when it comes to being a leader.