Agreed completely! Leonard Nimoy did a fantastic job directing. He knew exactly how to mix the drama and comedy, and got very ingratiating and genial performances out of the whole company, particularly Shatner.
A real classic.
Meyer had some comments about directing shatner - you would need to let him do it his way a few takes, so he would tire down and not over-act as much to get a better performance. he gives examples from the second movie where bill was hamming it up and they just had to keep shooting till he lost interest in continuing it.
taking this into account when looking at shatner overacting in most of ST V explains a lot I didn’t understand at the time about why that movie was so poorly acted.