That's stretching a point that's very thin to begin with. You know, I get that Niners think the show was wonderful. What you have to bear in mind is that
- There was a lot of real adult TV writing going on in the 80s and the 90s to compare DS9 with, instead of just sitting it alongside TNG and saying "oh, this is more sophisticated. Those shows featured substantial character development and serialized narrative that Trek never approached (other than maybe a bit during the Xindi year); and
- Most people who watched Star Trek to begin with gave up on DS9 during its run. By its third year in the series had lost more than half the viewers that TNG had handed off to it, and they never returned. DS9 is not a direction the Franchise needs to pursue.
None of which discounts that Ds9 was full of arc based story. Literally the whole thing, loads of them.
And I know... I was there. My favourite point of comparing then to now, is then we had Arthur Fancy and Ben Sisko, and now we don't.
And am pretty sure Ds9 was real adult TV writing.