During a rewatch, I remember thinking it seemed strange that Jadzia survived Change of Heart knowing that Tears of the Prophets was right around the corner and looked up the episode to see if there was any additional backstory. Turns out, Terry Farrell thought the same:
I tend to agree that ten episodes of morning and then Ezri showing up to get Ben from Sisko's Restaurant would've had a great emotional impact. Worf choosing duty and honor over his wife would've been very in character, but it definitely would've given all of them much more to play. Worf could've saved the symbiont but lost Jadzia in the episode, setting the scene up for Dax to come back as Ezri in Image in the Sand. They only would have needed another tragic event to trigger Ben leaving DS9 and going back to Earth.
They didn't even really use Jadzia to her full potential throughout the series anyway, but she was especially underutilized after Change of Heart. She didn't have huge dramatic turns that would've been affected by her absence, and in some cases they would've been made more resonant because of it. The Sound of Her Voice would've been heart wrenching knowing they were talking to a dead woman during her wake, then they would feel the absence of their fallen friend even more, her absence would be felt without even having to evoke her name. Plus Jadzia only had TWO LINES in that episode, explaining the wake:
Worf could've played his grief while any of the other characters could've explained what an Irish wake was, probably O'Brien.
She had 3 lines in Inquisition. She had ONE line in Profit and Lace. She fixes Quark's replicator in Valiant for a total of 5 lines. She has a little heart-to-heart with Kira in His Way, plus a little interaction with some other characters. All in all, she doesn't have much going on.
In The Pale Moonlight could've been more resonant since what spurred Ben Sisko to action in the first place was the loss of friends and colleagues because of the war, and Jadzia only serves as a bookend in this episode talking about death and loss anyway. Her biggest episode post Change of Heart is probably The Reckoning, serving as a conduit for technobabble and a sounding board for Sisko. She's in Time's Orphan a fair amount for technobabble as well, but that episode serves mostly to set up her wanting a child during Tears of the Prophets. (IMO a cheap tactic to make her death more tragic because she wanted a child, but I digress.) Even in Tears of the Prophets she isn't very present in the episode, since there are bigger plot points being played out on the Defiant and with Dukat. She gets a couple moments with the characters closest to her then a few measly goodbyes and that's it.
At any rate, all of her more important moments post Change of Heart could've been used to note her absence. If Sisko didn't have his sounding board and friend in The Reckoning, he could've lamented her loss. Kira could've mourned the lack of someone to talk to like Dax in His Way. The magnitude of the war and loss of life would've loomed much larger with the loss of a major character for half a season. Then Ezri showing up might not have been as jarring to the viewers as a replacement for Jadzia, instead been a more pleasant surprise to viewers with the same adjustment tensions with the characters