I really liked Ziyal (especially the third actress who played her), though I do wish they had done more with her over the course of her time onboard.
I'd liked to have seen a relationship between her and Jake, mostly for the reactions from both Sisko and Dukat--one not keen on it whilst the other would try to take advantage of it. This could also have seen some good moments for the Jake-Nog friendship.
I would have liked her to survive, though understand why she needed to die.
I also think it would've been nice to have had a reveal after her death, that Tora Ziyal was actually Kira Ziyal--Nerys' half-sister who Dukat fathered.
Just some thoughts I've had on Ziyal over the years.