Lots of thoughtful discussion and ideas about how to incorporate difficult dancers.
Splitting this into another variant of this discussion...
So...what happens if all of the attempts to shepherd and coach and "angel" the difficult dancer do not work and their skills and abilities continue to be a significant negative impact when they're dancing.
Would you ever (or have you ever) asked someone not to return based on their inability to dance?
I realize "inability" is a broad term and I intended it to be so for this question. There are lots of reasons why someone may not be able to know what to do and/or to be able to keep up when dancing and may not even be able to improve.
Is there some point at which you as organizers would consider and ultimately such a decision?