In The Passenger (S1E09), the first five minutes of the episode puts Dr. Bashir's arrogance front and center. Growing up, I don't remember Bashir being so arrogant but I too rolled my eyes along with Major Kira as she listened to him. Up to this point, the show depicts Bashir as arrogant, persistent (when attempting to woo Jadzia Dax), smart, and someone who knows how to spit game. Weren't ready for that last bit were you? There are at least two moments in past episodes where you see see how Bashir is a smooth operator. Spittin' some lines and getting the ladies.
What best way to undercut Bashir's arrogance and, hopefully, lead to a meaningful transformation as a character? Have this man's consciousness hijacked by an even more intelligent (and dastardly) individual named Rao Vantika who is willing to kill to stay alive. How well does the episode execute this? Not effectively I'm afraid. How can a man be transformed if he is unaware that he is a pawn in another player's game? There are no moments where we see Bashir puzzle out/explain away certain atypical behavior. Does he wake up and wonder how did he get somewhere while Vantika used his body to attack Quark? This is a route left unexplored.
Ultimately, the big reveal is underwhelming. I figured it was Bashir-turned-Vantika the minute he attacked Quark. Although we don't see him, there is no mistaking Bashir's whispered voice. Bashir has a distinct way of speaking that really can't be masked even if whispered. Perhaps it would have been more effective if Vantika spoke in his native Kobliad language. That would have given the reveal a lot more pop.
The episode attempts to conjure up some secondary conflict between Chief of Station Security Odo and the new Starfleet Security Chief Commander Pimmin. The tension exists all of five minutes before its resolved and Odo and Pimmin are okay. Why even bring this up then?
The episode is neatly tied up in 43 minutes and ends how it began about Bashir. He articulates humiliation but I couldn't help but wonder how are you really humiliated? This person did evil things unbeknownst to you. Or is it possible your arrogance to help a man that you were warned was extremely dangerous is what you bothers you. The emotional work wasn't there to lead to a substantive character transformation.