I liked Jadzia and was sorry to see her replaced by Ezri who never actually grew on me as a character. But I never actually found her annoying. (BTW, I loved Nicole in Dead Zone.)
I found Nog really annoying at first but as the character matured and found his own way that changed.
Rom, on the other hand, never seemed to change even as he bounced from bar lackey to engineer to Nagus.
Leeta had her annoying moments, especially in pout mode, but she did have her positive "attributes" as well.