I don't think that tall and lanky are requirements for the role of Millie. She's just got to be pretty, blow the house down with her vocals, and dance her shoes off. She also has to be the "girl next door" or "every woman".
Shoshana doesn't really fit the bill as far as "girl next door" type. She's much too non-average looking.
Hmmm... Good roles for Shoshana....
Winnifred in MATTRESS
Gloria in DAMN YANKEES
Ilona in SHE LOVES ME (but still a little young for it)
Ado Annie in OKLAHOMA
I think she'll probably end up being a glorified chorus girl for a longer while in her career ... until she gets old enough to pull off character roles. It's just a matter of time before she blossoms and finds just the right role for her to shine.
She is so fabulous in HAIRSPRAY.
She must be Fanny Brice SOON.
Itty Bitty Geisha?
Toyland?
Gypsy Pasadoble?
Just a few popular favorites...