The crummy first two seasons of DS9 did not help matters, it would be rather off-putting for new viewers/comers of DS9. DS9 is sort of like the ultimate in defered gratification (you endure the mainly so-so season 1, the almost directionless season 2, warm up to the transitional season 3, and whoop with joy when season 4 comes along and the rest of the seasons suck you in).
With TNG and VOY you could just sort of dive in at any point and understand what was going on because they were simpler series...
"Crummy"? "Directionless"???
Episodes like "Duet, "Necessary Evil" and "The Wire" are almost universally acclaimed. And then there are a whole raft of season 1-2 episodes which are arguably well-loved and regarded. Some of my faves:
"Emissary", "Dax", "The Nagus", "In The Hands of the Prophets" (a GREAT episode), "The Circle" Trilogy, "Whispers" and more.
There seems to be a raft of DS9 fans that seem obsessed by the Dominion war and the show only "got good" when it got obsessed with the war and every other episode was about how bleak things were.
I guess I'm in the minority then: Although season 4 is my favourite, I actually prefer (as a whole) the earlier seasons than the latter. I thought the show got too smug, war-driven and dull in seasons 6-7. Sure, there were some good episodes, but the overall tone I felt suffered.
I also have to pick you up on calling TNG "simpler" (I can't speak for Voyager as I haven't watched enough of it). If by simpler you mean "episodic", then yes, it was. AND THAT'S NOT A BAD THING. Simpler in terms of storylines? I'd disagree, but it varies (across both DS9 and TNG).
What's with some DS9 fans these days having a real arrogant streak about them?? It's probably a reaction to how we (DS9 fans) felt in the 1990s, when everyone was hating on the show. Now it's trendy and kewl to like it, suddenly all the other Treks are **** in comparison.