I have to say that I believe seasons 5-7 to be the pinnacle of Star Trek story-telling. I loved the mythology they created and how the show left me satisfied and wanting more all at the same time.
I tend to agree. I think the writers really embraced their exile and decided to push things as far as they could. And they didn't push just to shock & unsettle. It was always in noble service of the long established tenets of fine drama. It was always justified. It was always motivated and with purpose.
One thing I am also appreciating more this time around is Nog's arc. I kind of took that character for granted in the beginning, but the Jake-Nog friendship was much more special and important than originally gave it credit for.