Kira was a great character (probably my favourite in Trek). I don't see how people can comment on her actions, given the hard life she had. But over seven years she evolved and grew, maturing and accepting what she did.
As for Keiko, I never understood all the hate she suffers. Her marriage with Miles is very real, where they bicker and don't always see eye-to-eye, but love each other. I like that there are a couple of episodes where her knowledge and understanding of her husband play a key part.
Then there's the like of Alynna Nechayev who is branded a 'bitch' constantly. I have never seen her is such a light, but rather a flag officer in a key position who has to keep her eye on the big picture and not stroke the ego of the likes of Picard. She does what needs to be done for the safety of the Federation and Starfleet, which means needing to be forceful at times.