I don't get the hate about Ezri. She was a nice character and an interesting idea that helped give things another little shake up in S7. Yes, she was give a few episodes to develop and flesh out her character, but she didn't take over the series (like another female added to another Trek show). I personally would've liked the character to be male, just to have them really mess with the likes of Worf, Bashir and Quark.
I would have liked the next host to have been Odo:
That would screw with people in more ways than one.