The Lauren Bacall of "Waiting in the Wings" was many decades older than the snappy comedienne of 1956 and had lost a step. I remember Bacall had trouble remembering her lines and seemed to be paraphrasing speeches at the performance I saw. There were instances where Bacall had to stop the show and call for a line. Several years later I saw Rosemary Harris sail through a 25 minute monologue in Athol Fugard's "Road to Mecca" - twice! Flawless.
I think "Blithe Spirit" is helped immeasurably by cutting and I suspect the streamlined adaptation was done by the Master himself.
Delightful to see Mildred Natwick in her Broadway turn as Mme. Arcati - very different from Margaret Rutherford but delightful in its own way.