I love Ricci's memoir!
I always think back to the passage where she discusses making a minor change to the principal's blocking (IIRC it was something like she removed her glasses for the "Yes, I've always been green, no I didn't eat grass a a child, etc" line at Shiz, which the principal at the time didn't do) and she was told in no uncertain terms to never do it again.
The passage related to the incident:
"Like every long-running Broadway show, replacement actors across every Wicked company had to be derivative of the actor who came before them. Standbys, in particular, were coached to stay within the shadow of everything their principal actor did (for consistency and safety when interaction with other people on stage). In short, unless you were originating the role in a company and working with Wicked’s director Joe Mantello, there was only so much an Elphaba could do. It wasn’t about painting a new landscape; it was about coloring within the lines."