E: These are the things we know about the way the show picks the Top Twenty:
The dancers are, of course, ridiculously talented.
They are also, in their different ways, ridiculously decorative.
Now, if it were just about dancing on a stage, those two factors might be enough – especially when combined with aspect we don’t see as much of, like attitude and work ethic and the ability to play well with others. But this is about casting a TV show, so there are other obvious factors.