How will this affect any feelings Odo has for Kira? I mean, it's hard enough for Odo to admit he has romantic feelings for anyone. But he finally did so with for Kira (although he still hasn't told HER). You know how first loves are; certainly Odo felt it was special, one-of-a-kind, would last forever. And all that's still probably true, but it does certainly change things when you have your second love, when you admit that there's more than one person who can get your juices flowing (or whatever the equivalent is for changelings). And boy, was Odo moved; he allowed Arissa to get away with things he would never allow Kira to get away with, no mater how much he loves her. But maybe that's because Arissa was so much more vulnerable/needy than Kira. Or maybe it was because Arissa was literally programmed to be someone he would help. Her personality was, after all, made-up and programmed by someone. Funny that a man that didn't want to play with a fake holosuite girl ended up playing with a different kind of fake girl. (I won't get into the legal ramifications of over-writing someone's memories and personality and how someone was killed in those actions.)
You think maybe this will soften Odo some. Make him realize there's probably someone else out there for him. I would think it would make his connection with and interest in Kira just a little bit less significant, less of a driver in his life. Hey, does that mean he'll be more likely to leave DS9 and return to the Great Link or something, since Kira was what was keeping him here?
What I did like about the episode was the scenes in the holosuite and the exploration of the Orion Syndicate criminals. But I just generally didn't find the story very believable. Odo seemed so out of character.