I also was thinking that Lea is bit young for Elphaba. I'd love to see her in it when she's older. I've never heard her belt anything. Sparing Awakening doesn't seem like a challenge vocally, to me. But someday, I;m sure she would make a terrific Elphaba.
"Some stories don't have a clear beginning, middle, and end. Life is about not knowing, having to change, take the moment & making the best of it, without knowing what's going to happen next. Delicious ambiguity."
-Gilda Radner