I love the tone of old trek now, didn't used to, I love the attitude of excitement the music invokes, as opposed to an attitude of terror. Go ahead listen to the musical score of modern trek during an attack scene, pure terror, no excitement, only fear and rage.
Imagine if Kahn had joined with Kirk, we get some people who have the same gene modifications in later series who work in starfleet but their abilities aren't impressive looking because by then we're used to having shapeshifters and super androids and shit