Here’s another case I’ve thought about
In "Obsession," (spoiler alert) Kirk sets off a bomb that rips away half a planet's atmosphere and presumably ends all life there. The remaster adds a cool touch, showing the planet slightly scarred as the ship pulls away at the end. Note that the original fx showed you nothing of the damage done.
I found myself wishing CBS had done a little more, like showing a debris cloud erupting from the now-dead planet's pulverized crust. It would clash with the happy ending and upbeat music score as the Enterprise sails away, but maybe that very clash would add a jolt of realism and irony to the episode.
The macho, non-hippie '60s ethos (which I love), where the good guys can blow up a whole planet and think nothing of it, and Now it's Miller Time, would be highlighted and recognized better with more vivid planetary devastation in the new fx.
It would up the ante a little on the portrait of Kirk as a space cowboy who plays by nobody’s rules but his own. He wasn’t going by the Carol Marcus ethos (“there can’t be so much as a microbe…”), based on the fear that sentient life might evolve billions of years from now if only we don't disrupt things. He would have sputtered at that and said “You’ve got to be kidding me.”