If you have even only one good improviser on stage, nobody on that stage is a bad improviser.
This is a very bold statement to make. I love it. It tells us that the strength of an improviser lies in making your partner look good, in (over)acceptance.
It reminds me of shows where improvisers create scenes or even longer stories with random audience members on stage. If they do it well, the untrained improviser will still look very good.
Powerful wisdom, this one.