I know an instructor who has a broad build and isn't the stereotypical (in my most PC language) shape for an instructor. BUT she can lift some of the heaviest weights (Pump) and get into some of the strangest shapes (Balance) while providing that awe inspiring experience. I myself am not stick thin and well toned but I have the fitness to get through the class and give an inspiring workout. Truth of it is, not all participants are stick thin and muscular either. There are some people that are inspired by that physic and some people that are intimidated. All types of instructors for all types of participants - SO LONG AS THEY CAN DO THE WORKOUT!
Lets not forget: its KEEP FIT not KEEP THIN
