For the up close shots in numerous Trek episodes, it often looked to me like the actors were going thru the same fight choreography and doing a fine job of it, and I wondered why even have so many cutaways to the not-long-enough long shots of stunt guys whose primary job was definitely not looking like the actors they were doubling!
Like that Kahn fight, I was impressed when Shatner leapt up and grabbed hold of the grill and wrapped his legs around Montalban's neck and then let go of the grill! Even though I'm sure there was plenty of cushion to land on beneath them, it was a great shot. I think they just lingered too long on the two stunt men during the wide view of the fight.
I think their best approach, when it really clicked, was when they utilized stuntmen and actors at the same time. Like when Khan explodes out of his quarters and smacks the hell out of the security guard by the door. Or that time Spock grabbed hold of a charging grunt and hurled him way down the corridor. Stuff like that really sold the greater-than-human strength idea.
Back to the Khan fight, perhaps they could've had more long views of Shatner fighting Khan's stunt-double and vice-versa. There'd be a lot more setups involved there, though, so it would probably be prohibited by time.
Haha, I just checked out the fight with Tracy again on the 'Tube. Yeah, it's just Shatner and Morgan. Good stuff, particularly at the start when he hurls Shatner down to the floor none too gently. I thought Tracy was a great villain of the week. First he had the crazy eyes, and then they gave him an Axe, and then there's the knowledge that he's also a Starship Captain with at least equal training and experience. That guy was intense and I remember actually being scared for Kirk as a kid.