(You all just knew I was gonna drop in. Admit it.
Needless to say...I completely disagree with the OP. Ezri is one of my favorite characters in the Trek
universe. She was
needed, thematically, as the show hadn't had her kind of personality on a regular basis in a LONG time. Story-wise, her presence was a constant
symbolic reminder in the final season that "life marches on"--an element of hope, that the darkness is temporary--that "we will recover".
And as a straight guy with a thing for said kind of personality, I'm glad she wasn't a guy.
Besides...while I'm all for "dramatic potential", the simple fact was the series was almost over
. No need to make things more complicated than they had to be. Better to give emotional closure
to the characters--Sisko, Worf, and Bashir in particular, but also Quark. Sisko had to overcome the depression he got after losing Jadzia...and the other three had to deal with their respective relationships/feelings involving Dax. Somehow, I doubt the Ninth Dax being a man would've helped much, on that.