^I don't know. If Odan had been a chick and Dr. Crusher a lesbian, I wouldn't have expected her to pursue Odan's replacement if it turned out to be a dude.
Love is highly tied to sex and attractiveness and I'd say generally most people would not embrace a transgendered version of their mate, and not for any particularly bad reason. The more enlightened could still be close friends, but generally I'd suspect the romantic attachment would be lost between both of them--unless they were bisexual in the first place. Trill are, almost by default and possibly as a result of the inevitable gender-bending of their life cycle. We don't know about Worf, but there's no evidence to support it, and it would've come way out of left field ten years after we met him.
For an episode dealing with gender themes, The Outcast is far superior than The Host imo. It's somewhat criticized, from what I gather, but it's in my top five or so. Again, one
can make the case that one was a copout, too, because they had an actress playing the role and Riker going for the old fibrous husk.
A better argument could be made for copping out here, I think, than with The Host, although again I'd point out that doing so otherwise would have to make Riker at least a bit bisexual, when he'd never been written that way before. I'm not by necessity making a case against that, Riker trying to hit anything capable of consent could have been potentially awesome and would not have been far off from the portrayal as it stood.
However, if TPTB wanted to deal with the issue in a less sensational manner, instead of exploring human sexuality with aliens-of-the-week and stopping short and apparently disappointing people, they should have had a gay or bi character, built from the frame up as gay or bi. A gay Jake Sisko and Ben treating it as a non-issue would've been a fantastic statement.
Unfortunately, they didn't want to do anything other than a psuedo-lesbian bit with Jadzia, and just like in The Outcast, we know why women were chosen to explore the issue (and not just because the only Trill was portrayed by Terry Ferrel, who had been a woman since at least The Emissary

). That they didn't do this, or go farther with Jadzia, is easy to blame on society, but Trek's not supposed to be about that, it's supposed to be about what society should be. <_<
As for Ms. de Boer, the Andorian idea's not bad by half.

But Ezri brought something to the show that it needed, and I'd have missed her character. I understand the argument that a male character could have served much the same purpose, but--and this is the whole gist of my post--gender isn't interchangeable.