One interesting version that I'd like to see is them bringing in Ro in season 4 instead of Worf. Worf already has seven seasons of TNG and was there for the movies. And yes, the interactions between Kira and Ro would have been very interesting. To top it all off, they could write a romantic relationship between Jadzia and Ro...
While I agree that the romance would not have been possible at this place and time, I would have loved Ro instead of Worf joining the cast, balancing the m/f ratio a bit, but most of all because of the interesting dynamics.
Also, we have never seen an intense, interesting, deep friendship between two women on Trek. Like, say, Bashir and Miles, Garak and Bashir (never mind what else it could have been), Spock and Kirk etc. (Burnham and Prime Giorgiou might have had the potential.) I would have loved to see that. Either between Ro and Jadzia or - despite their possible conflicts - Ro and Kira. Of course none of them was redundant just because they were both Bajoran ex-terrorists.
Behr recently mentioned that they dropped the ball by not exploring a deeper friendship between Kira and Jadzia, and I agree. But with 3 female characters to choose from, maybe one of the other combinations would have worked better anyway. Just because Kira and Dax were the only women on the main cast, doesn't mean they are automatically soul sisters.
Unfortunately there's a difference between a kiss and a relationship.
And it can be argued that it wasn't even a kiss between two women, primarily, but rather between a married man and woman who now happen to be in different bodies. They played it safe, and probably had to.
On my rewatch I discovered that "Rejoined" isn't half bad, particularly considering Trek's track record with romance, but at the time I thought it was a horrible, lame cop-out.