TMP was a strange, hybrid beast. It ranged between a shipwreck and beautiful. For the first time, I could really deconstruct what I was seeing. I could spot where the various teams went right and wrong. I could also spot where Gene Rodenberry needed a punch in the face. He was a capable enough TV hack, but those skills neither translated well to film, nor did they apply well to future TV. This all shows painfully in TMP, where we have a character driven cast with a non-character driven plot. Heck, the writer introduces two prominent characters that none of us cares about, and who crowd out the cast that we like.
This all turns around with Wrath of Khan. The film is character driven to a fault. Even without the McGuffin of the Genesis Device, the film would have all its intensity. That's the key. It's not about rallying to save the world (which is the standard film plot these days). It stand out because it's NOT about the fate of the world. It's about the fate of a character that we like.
Yay for not saving the world.