...It shows Commander Sisko not quite at a captain’s level of dealing with some situations. I think that was the point of making him one — so we’d see some mistakes. Picard had been a captain on two ships by the time he got to Vagra III. Maybe Sisko would have lost his cool with Armus and gotten more of his crew killed. Armus was all the negative and ugly that remained of his people. I think if they fed that anger with more anger, it’d only add to its power and play further into its game.
I don't think the point of making Sisko Captain was to see him make some mistakes (though he certainly did make some). I think it was to show growth. Late-DS9 Sisko is a very different person. A person who not only has been Captain for several years, but fleet commander, a diplomat who has to juggle between Dominion, Klingons, Cardassians, and Romulans, and a Bajoran religious icon to boot. I'm fairly certain that that Sisko wouldn't have let himself provoke that easily.
And let's be honest: at a similar point in TNG's run (I believe Q-less is the 7th episode of season 1? ) , Picard still came accross as mostly a child-hating, grumpy, somewhat pompous older man. He didn't show his great diplomatic skills and his friendlier side until later in the series.