I haven't posted my thoughts on the series in awhile, so I thought I would add them to your thread.
I think the fact we are still in here talking about the show is telling of both the Trek universe and DS9 as an individual series. I think Berman, Behr, and Piller put the universe that they created in TNG to the test. If TOS was morality plays, so was DS9 and that made it uniquely Trek. The series that followed after DS9 do not inspire me.
I think of DS9 as a 177-hour story about Oppression. I think the show did a good job at showing what it was like to have to make peace with your enemy. We made peace with Germany and Russia. It happens, and that is what the Cardassian/Bajoran relationship was to me. I think it was of its day to make the Cardassians so obviously the bad guys. There's no ambiguity from the time that Dukat came on the station to welcome Sisko to the neighborhood. They correct some of that by making Dukat more sympathetic until the Cardassians join the Dominion.
I think the weakest part of the series was the Maquis. I have wondered if they intended to split the Federation in half or if they were trying to find a way to fight another war with the Cardassians--the Cardassians are honestly arming the other side and the Federation has no choice but to try and stop them, that sort of thing. It seems to just sit there. They repeat themselves over and over again. I understand that the colonists want to go home, but it doesn't peel the layers like it does with the Dominion.
Anyway, the Dominion is both the oppressed and the oppressor. The Federation finally faces the situation that the Bajorans faced before the series began. Will they be oppressed as well? Or, perhaps worse, will we destroy ourselves because of the existential threat?
DS9 remains the best show at really picking apart a problem. The problems will be there next week, too.