Music isn't terribly important to me - I honestly couldn't hum a score from TNG or DS9. If I notice music enough to remember it at all, it's usually because it's incredibly bad or overly intrusive. I wouldn't say the TOS music is bad, but it's certainly crazy intrusive. Like there'll be some banter between McCoy and Spock and these woodwind things will come blaring on like BUM-BA-BA-BUM-BA-BUM-BA-BUMMMM just in case a deaf guy two towns over hasn't realised the scene's being played for laughs.
I assume it was standard at the time, but it really hasn't aged well.