Also I strongly argue that Empath is very character driven. In fact one of the most character reliant episodes.Thanks. That's the great part about different interpretations.
You substitute Picard, Riker and Data in you might get the same result in the end but the journey would be way different. And thats because ... Kirk, Spock, McCoy love each other. Not in the fan-fiction way but as close as bros can be while denying it.
You could argue that Spock wanted to sacrifice himself because he was the senior officer, because he was the strongest, because he didn't want Kirk hurt making the decision or that he didn't want McCoy to come to harm.
I just don't think that another set of characters would do the same. I'm probably alone in these thoughts as no-one else here seems to think that The Empath is a great episode. You could argue well it was the actors that made it work. Nimoy looking up at an injured Kirk.
The main thing I remember from the episode was the character interaction not the planet-saving story.
I also think the episodes where Kirk's mettle is tested as a captain are rather character driven like "Balance of Terror".
There's at least a dozen other episodes where I think we care more about the characters than the actual result of the story.