Repetition is good, much repetition is better. The danger is that after doing it over and over one tends to get lax. Like a good singer or stage actor, each performance must be done with spirit as if it was the first. That's one thing...
But repeating it exactly the same way will not give optimum benefit. A simple reverse punch has perhaps 30-50 or more "data points" that can affect the result. A little more or less hip, how the weight is transferred with the legs, the exact amount of tension or relaxation at each point of the punch, breath control, etc. And each of these have various inflection.
Like cooking, there is a basic recipe that should be followed, but beyond that, experimentation is needed to come up with the exact taste that's best for any particular individual. A little more of this spice, a little less of that, how much time at what temp, how much stirring, and so on. It requires a lot of tasting on the way to your own perfect dish.
The same in MA technique. You won't know exactly what it is until you feel it. It may take 5,10 or 20 years (as in my case) to stumble upon it. (Not that it wasn't excellent to begin with.) It's not what you do, but how you do it. Sometimes it's not a physical thing, but an attitude or spirit that can make that tiny adjustment that yields a big change in the nature of the move. A 1% change can make a 10% difference. All the above, mind you, is just for a single technique!
Some have posted questions on what there is to learn after 5th, 6th or 8th degree black belt. This is an answer.
So, in doing all those reps, they don't have to be all the same. Each one can be a journey of discovery.
)
