I've always thought of Shirley as a character actress, even though she was a quirky leading lady. She does have a bit of a European sensibility (perhaps from one of her former lives?). While she kinda sucks with accents, she doesn't suck at playing all sorts of characters, rich or poor, comedy or drama.
Debbie Reynolds was and is a personality. A megastar in her day, and she was the best Debbie Reynolds there ever was. Still is. She has a huge presence, and a very likable one at that.
The closest I've seen her play "out of her skin" was in "Mother." And she was still Debbie Reynolds as Mother, for the most part.
I don't deny that she would be entertaining and engaging as Mme. Armfeldt, and she would sell tickets. She would not, however, "embody" the role. It would clearly be Debbie Reynolds on stage.
The producers wouldn't care about any of that. They would likely stop at "Debbie Reynolds would sell tickets," and leave it at that.
"Jaws is the Citizen Kane of movies."
blocked: logan2, Diamonds3, Hamilton22