Ripley was thrilling the night I saw her in NEXT TO NORMAL on Broadway, as others have said, it's a shame that she has damaged her instrument but her acting choices in that show were quite spectacular and made me think she'd make one hell of a Sally.
I can't imagine Elaine Paige as Sally at all, not only do I have zero interest in seeing her play that part, but when I think of her big roles (and obviously British audiences are probably more familiar with her range and roles she's played) I think of Eva Peron, Norma Desmond, Reeno Sweeney, Drowsy Chaperone (maybe not a big role since the show was such a bomb in London but it's a recent role at least), Mrs.Lovett, and now Carlotta...nothing in her resume suggests she could capture the fragility and complexity that makes for a great Sally.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"