I think Kira's conviction definitely comes across in "The Darkness and the Light". The scene with her beating up 3 guys on her way to the bomb site comes to mind, but the scene that I really liked was:
Odo has a list of possible suspects, but doesn't want to let her see it, afraid of what she'd do with the info. So, Kira pretends to be tired, let's Odo walk out of the room, them beams to his office and gets the list and then leaves the station -- all before Odo even gets back to his office. Brilliant!
Still, she was probably showing too much conviction. I mean, do you really want to go after a dangerous killer while pregnant. And I'm not talking about the handicap it gives you in any fighting you have to do. I'm talking about the danger you are putting that unborn kid in. Do you think she still would have been so gun-ho if that was her own kid, versus just a baby she's carrying?
While I generally like Kira, this may actually be the episode where I like her the least. Because she wasn't concerned about the "rule of law". If that was the case she would have just told Odo who to go after versus going herself. She wanted revenge by her own hands. And she was willing to endanger the baby (as well as disobeying orders, etc) to get it. She doesn't really come across in a good light.
Some may argue, as they did her, that Kira still maintains her angrier, younger self and will revert to that from time-to-time. I guess that's true of all of us, and it does make her more real. But I would have hoped she could have been better than that. I like my heroes to be more heroic.
Loved the little continuity nod with Furel and Lupaza showing up again, even if it was just to die.
Great seeing Nog continuing to do well in his chosen job as a Starfleet officer, and especially because he's using his unique Ferengi skill-set to do so. Pretty good for a guy that couldn't read 4 years ago.