People who criticise the Roddenberry vision frankly miss the point, and essentially the point of art (a TV show, especially a dramatic one, is still art by definition). No art form must absolutely correlate with reality, and to suggest as such is silly. I doubt the Great Bird, who was seemingly an intelligent man, believed his vision was reality. It is essentially a hope for the future, and to be taken in that context alone.
I didn't have a problem with his vision of sunshine and lollipops and everyone working for their own enlightenment.
But from a purely story-telling POV, I think DS9 holds up moreso than TNG because there's conflicts from within the cast. More often than not on TNG their conflicts extend from external pressures; and while many are still better than much of what passes as television today, that whole model of "no internal conflicts" was going nowhere fast....even moreso with Voyager, where there weren't even good stories to make up for that.