The introduction of Section 31 gave everyone something to talk about. Far Beyond the Stars was an artistic masterpeice. And the death of Jadzia Dax, I must say, the writer of the editorial has it all wrong. Terry Farrell wanted to leave the show. True enough, she didn't want her character killed, but she did make the decision to leave. That may make her character's departure seem out of place, but none the less appropriate. The Dominion War has been faught, officially and unofficially since Season 3 (which began with major tensions with them) and lasted until the very last episode of the series. It is only logical to conclude that someone will die. Sisko reads through thousands of names of casualties at the hands of the Dominion, yet he never lost anyone of his crew until Jadzia. This makes it much more potent...it makes the war seem personal...and the Devil (Dukat) is a more real enemy to Sisko than the Dominion.
Art, plan and simple.
One of them of course is the use of long, involved story lines. Almost more than any othe sci-fi series (with the possible exception of Babylon 5), DS9 showed that war was a messy, complicated business, not just in terms of body count but in compromised values, shifting allegiences, and tough decisions that may or may not be right. Sisko truly comes into his own as the leader of the station as well as a key figure in the war. The highlight of the main war story arc is In the Pale Moonlight, a true masterpiece of storytelling about the seamy side of war. Almost as good as this exceptional episode in the general story line is Inquisition, which introduces the KGB- or even Gestapo? -like Section 31(and they work for the good guys!)
Every Trek season has it's off-topic type of episodes, and season 6's are some of the best. Even the Ferengi episodes are not that bad - The Magnificent Ferengi is a comic highlight. Who Mourns for Morn is uneven but nevertheless makes use of one of the most famous non-speaking parts on TV, Morn the barfly. Statistical Probabilities is a very interesting intellectual episode that furthers the story of Julian Bashir as a genetically enhanced human, and shows what can go wrong with such "enhancements". Valiant shows the effect of war on kids (a young Academy squad who somehow end up commanding their own ship after the death of their captain). One Little Ship is a ridiculous but totally fyn episode (Honey, I Shrunk The Runabout!) His Way introduced James Darren as Vic Damone, a holographic night club owner with self-awareness - since Voyager was pursuing the idea of a hologram being a sentient being, this was nice to see - and Vic becomes an important secondary character in season 7. Worf and Jadzia Dax's wedding (You Are Cordially Invited) is a bit cheesy, as many Kllingon episodes tend to be. But the Worf-Jadzia relationship was one of the very few marriages shown in Trek (aside from the O'Briens), and later episodes managed to show the difficulties of being in the same war with the one you love quite effectively, until the death of Jadzia in the last episode. The death itself was quite abrupt - almost up there with the death of Tasha Yar in TNG, but in the context of war it makes sense. Death in war is senseless...
I left the best for last - Far Beyond The Stars. This is a transcendent episode, and a must-see for any sci-fi fan - even if you don't like Trek. It asks the question, are we real? Or are we just a figment of someone's imagination? And what is it that makes what we dream of? This idea was explored somewhat in a Next Generation episode (Message In A Bottle), but it's really told beautifully here.
I can't really think of a truly bad episode in this season, like a couple of the clunkers in both season 5 and 7. All in all, this season is a keeper.