If Dax had returned as a male, then the only woman on the main cast would've been Kira. It was a good ensemble cast, but that it needed more female characters.
At any rate, I can't fathom the dislike of Kira either. What was offensive or off-putting about her?
I didn't like her personality and I didn't like some of the pretty dull episodes which centered around her (I recall one in particular where she was trying to get some Bajorans to leave their homes which was particularly bad). I also found the Bajoran's to be one of the dullest ever people to be portrayed on Star Trek, so whenever she doing 'Bajoran' things, it bored me.
In retrospect I agree about the lack of female characters if Dax came back male. I would have just preferred a better female Dax to have been portrayed.