What makes Duet great is because it was an exception, but not the standard for DS9 at the time.
Season 1 DS9 still has episodes that bring it down.
If Wishes Were Horses: The Rumplestilskin episode
Move Along Home: Allamaraine, count to 4, allamaraine, then 3 more.
Q-Less: Where Vash and guest star and bicker over things we never saw and aren't interesting.
I think only TOS has the best ratio of great episodes to poor episodes, in their first season.
True, good point--for the most part, season 1 and 2 were more bland and silly, but part of the reason I think, was because it was imitating the TNG style while it was developing.
Take Kira's hairstyle for the first part of season 1. It was exactly like Ro Laren's from TNG.
It's was the idea, that she's Bajoran, and all people from the same planet have the same hairstyles.
Then they changed it, and Kira's personality seem to emerge even more.
I've discovered that some of the early episodes were more meaty than I thought at first.
Like In the Hands the Prophets. It was a direct subject on religion vs science in schools.
Usually the other Trek shows would use an analogy to tackle a subject like this. DS9 made it an actual situation that happened to them.
With a school being bombed and religious fanatics and debates.
And the situation didn't completely resolved itself, only the culprits were caught, and cooler heads prevailed, but it was still a lingering issue.
And that was because of the serial nature of DS9--otherwise, on the other shows, it would have been solved and forgotten.