It's sort of like nesting dolls, isn't it? Shakaar's character is watered down so his purpose is to fit inside Kira's character package, while Kira herself is watered down (in this episode) to fit inside Odo's. Shakaar's role is to be Kira's Boyfriend, and Kira's to be Odo's Not Girlfriend. While I love Odo episodes, it's a shame that Kira had to be temporarily diluted (and poor Shakaar never recovered). It was a bit too Odo-centric, not just in terms of focus but in how other characters were presented. Although maybe that does serve to highlight Odo's loneliness and general alienation.