I watched this episode many times. Deep Space Nine is by far my favourite Star Trek show. I felt this episode did bring closure to the show, but the way in which it was done was a big surprise.
I was disappointed where Dukat ended up, just because I got bored with him and Winn. But it was the storyline that in many ways was required. The prophets have always been a force within the storyline of DS9, of Bajor and Cardassia. The war with the dominion seemed to be the main focus, but the prophets always had to have an ending, as did Sisko as the emissary. It was sad he left Jake and Cassidy Yates. But you maybe wonder if ever since Jennifer died, his life was set on a path and he that path had an ending with Bajor. After all we know that linear time, does not exist for the prophets, in other words, the writers did what had to be done, finished what was already written for his character and gave Sisko himself closure of sorts.
I also found the Cardassia angle brilliantly written. I have always been a huge fan of Garek, he is a brilliant character. When the founders ordered the extermination of the Cardassian people, followed by Martok offering a toast to victory amongst the ruins and dead of Cardassia, suggesting in some way it was poetic justice, Sisko's reaction reminded me of one of the tragedy's of world war II when Germany was reduced to dust and the russians and american's met in Berlin. In Garek's discussion with Bashir afterwards, he stated it was heartwrenching that their culture, their music, art, literature etc. Great people were gone, but said that we were guilty for our arrogance. I felt in that portrayal the writers really took from our own history of War, one of the many tragedy's that all of us will lose much that is dear and we will all reflect upon how arrogance brought it all to this point. Sisko clearly felt too, there was no victory, just such sorrow it ever had to come to this.
For all these reasons I give the episode top marks as a really intelligent ending to a show that in my opinion was far far deeper, far darker, with personalities and storylines far more real than anything Star Trek had before or after. Deep Space Nine was a very unique show and I think we have Ronald D. Moore to thank for the pleasure and sorrow of this ending.