I think that had more to do with paying her royalties for using her likeness than anything else. Jadzia was easily my least favorite of the main cast, but I did feel her the lack of clips of her in the finaleYeah, the total exclusion of Jadzia in the last episode was very disappointing. You know, to omit her wedding to Worf, etc was inexcusable.
I don't find this sad, however. I feel that, moreso than any other Trek cast to date, that all of them had story arcs and they all grew as people and this finale gave them all closure. Kira/Odo's split was indeed bittersweet, but they've gotten what they both wanted--Kira to see her people truly liberated, and Odo to find his place in the universe. Worf, too, has earned a place within the ranks of his fellow Klingons and even for the short time Ezri had on the show, I felt she too closed up a lot of Jadzia's journey too while adjusting to being Erzi Dax.And that's to say nothing of the side characters who all had more character development than the leads from Voyager or Enterprise got.
TNG, while a good solid episode, was still mostly just Picard's story and kept the status quo because of the upcoming movies (besides the out of nowhere Worf/Troi thing that ends with no onscreen explaination). But then, the TNG crew were all happy go lucky. Voyager's Endgame minus the Chakotay/Seven crap was serviceable enough. TATV needs no explaining.
TLDR: I don't think it's sad at all.