Is variation in the movement a bad thing?

It may happen that when teaching new behaviors to our dogs, we would like all the repetitions to become as similar as possible. Especially when training something for competitive sports.

Let’s look at this from the movement perspective. What does good movement skill tell us? Does good movement skill mean there is no variation in the specific movement over the repetitions? Or is it the opposite – in order for the movement to be skillful, it needs to have variation in it?