Since DS9 or ENT or JJ? Or TOS with "Let That be Your Last Battlefield"?

As long as they keep some optimism or other Trek values, a little liberation does open up more storylines. (the flip side to optimism is many TV episodes end way too happily and/or neatly/simplified (for a show that's a metaphor about the complexity of our society), the most glaring of which are "Bar Association" and "The Cloud Minders".
The problem is that these people have to say something, even lie, to throw off audiences, since a big revelation exists in the plot and those people are trying to salvage it for the majority of the audiences that probably don't want it spoiled for them. Especially since someone leaked "Spock is going to die!" in 1981 or so, though look at how well that turned out by comparison. Yet despite being a semi-clone of TWOK, nobody spent the 11th hour trying to hid the fact that the dude was Khan (sorta, maybe "NuKhan" or "Alt-Uni-Khan" or something but for all the issues, I did like the altered history regarding the setup and imprisonment of his people.... of course, one of those renames sounds rather like "unicorn" but nobody's perfect...)