I think that DS9 is what it is because of what came before. DS9 benefits from TNG (and obviously TOS) building up a universe to play in.
Indeed....My own opinion on the matter is that TNG and DS9 each built upon what its respective predecessors had established and improved upon those predecessors in many ways. VGR and ENT, by comparison, rehashed TNG rather than improving upon it.
I'm also of the opinion that DS9 is the only Trek show that consistently improved upon itself right up to the end, whereas TOS and TNG both peaked somewhere in the middle and went downhill a bit before ending. We'll see if that 14-year-old opinion holds up as I revisit the series.
I'm currently very early in a long-term rewatch of DS9, so I'll probably be hanging in this neck of the BBS a bit more often.