I agree. I could deal with everything right up until she was piloting the Defiant. I can't imagine she was the most qualified officer for the position. Regardless of Dax's history, Ezri did not have the experience to justify it. Lazy writing. They took the easy route by essentially replcing Terry Farrell's chacracter with a new actor, but cut her hair short therefore making her
completely different.
A man would have been the better choice. I get all the reasons they didn't, but if DS9 were made today I bet they would. They could have solved the woman shortage problem by giving Keiko or Kassidy more prominent roles (which happened for Kasidy in the final arc anyway).