As for Kira as a character, sure I understand what you guys are saying, and I completely agree. The problem it seems to me, is that Nana Visitor did not understand how to give that character some nuance.
If you ever see people who have PTSD, they tend to have short bursts of anger, but mixed in with other things, like paranoia and fear, etc etc.
Why can't Nerys simply be an angry woman? I never thought she had PTSD, only that she is (understandably) angry in general.
One of the things I love about DS9 is that the characters actually do evolve over time. I'm betting you'll come to like Nerys during later seasons.
Nuance? Let's see how you feel after Progress