I always find it bemusing how people equate perceived 'grit' with 'realism' especially in regard to Star Trek.
The humans too perfect? That was sort of the point to Star Trek in a lot of ways, it's optimistic, we all get to be better versions of ourself in the future...humanity gets more civilised, not less, not the same, but better (sort of the opposite to cyberpunk, and we haven't improved much recently in the real world either)
Star Trek, like most optimistic sf, is about what we can be if we try...and revelling in the negatives of our species to declare it 'realism' seems defeatist. It also seems that one aspect Ds9 highlights is already true...it's easy to be a saint in paradise. and the flipside is we turn to entertainment to use what are essentially bad things as entertainment. I think the very things that people think make their entertainment 'realistic' are the very things that would break them if they were actually happening for 'real' to them.
I can assure you that those who experience problems like war, poverty, religious persecution, etc, arent necessarily going to enjoy being told that the same stuff will still be happening I'm the future here. But being shown a future where everyone is sheltered, fed, can do well according to their talents? A future where when these blights are found elsewhere, humanity will help those people too?
That's a future that gives a bit of escapism, that gives a bit of hope.
There's enough entertainment out there that revels in the more unpleasant side of human nature. Trek is rare that it for the most part does not...and that includes Ds9, because it shows people, humans, making the universe a better place, and that includes Ds9.
Sisko, even in his darkest hour, is still fundamentally trying to keep that light of the Federation burning...you can't sing the praises of The Pale Moonlight without also remembering Home Front and Paradise Lost. You Can't be militantly atheist about the Bajoran religion, because the Wormhole aliens are also Gods, and the persecution of the Bajorans by the atheistic Cardassian Union shows where that can lead you....then the Ancient Bajoran caste system shows you exactly where blind faith can get you.
Ds9 is rare in that it's gritty 'realism' actually is realistic in its analogy, which puts it's square in line with TOS and TNG...and it still shows a future of hope. Sisko said he isn't Picard, but the reality is they are both those 'evolved' humans...Sisko was maybe a little more broken at the begining, but ultimately that starfleet crew are not on Ds9 to benefit themselves are they? Sisko can have a nice safe job on Earth, but even before the dominion threat he chooses to remain on Ds9.
I prefer the hope. I am not looking for defeatist fiction, showing me a future where we continue to struggle against each other, where the haves are comfy in their little world watching 'realistic' entertainment because their world bores them and they are too cowardly to seek real improvement and real challenge, and where the have nots have less and less escapism even in their entertainment, and little to no real escape from violence or poverty, caused by greed and selfishness, around them.
So yeah. DS9 works very well with Genes Dream (not so much the dollar signs version, but it shifted more Merch than enterprise and jj trek combined) and reminds us exactly why we have it in the first place.