Don't be silly. Keiko
was the most annoying character on DS9 by a long shot.
And, of course, they had
to replace Jadza with another Dax. The symbiote thing had been set up years ago; how on Earth (or Bajor) do you resist an opportunity like that? It was like a gift from the writing gods (or Prophets).
And Ezri turned out to be very likeable and appeaing.