> High performing teams made to do agile become average teams and low performing teams made to do agile can become average teams.

This is also my observation. I compare it to McDonalds vs a star restaurant. Put the top chef of a star restaurant in McDonalds and he will perform average. Put a McDonalds member in the star restaurant and he will perform badly.

The amount of process needs to be tweaked to your team. Ideally, you can give your star players more freedom.