Stacy didn't pick herself for this show--the producers did. Maybe they shouldn't have, but since they did I'm not going to take it out on her. I'll merely wish they cast a bit more evenly in the future. Heck, even Drew might have been uneven casting. Ideally ALL of the competitors would have been at about Lisa's level--people with a ton of potential and SOME minor dancing background (I seem to recall something about Lisa having some as a kid, but nothing on the level of Stacy).
I think the biggest thing going for Stacy--more than jazz dancing/cheerleadeing--is ballet going back to childhood. And that's not something restricted to either pros or competitive dancers. It's why she gets all those glowy comments about posture. A mere jazz dancer wouldn't get those.