Just because someone is an expert dancer it does not mean they'll make a great judge or even a decent panellist, week after week.
I have dealt with clients who want to go on panels and have to deflect them, not because they did not know their stuff, but because they did not have what it took.
Karen's curse is that she is totally self-absorbed, rarely stops taking about herself, never stops banging on about her and 'Ramps' and comes across as totally insincere. She gushes and gurns incessantly, and that is dire on TV.
She is also a tad blowsy and would need a make over to stop her looking like an off duty air hostess ready to hit the wrong side of town come 10pm.