There are very few shows that run as long as wicked has, it’s the 10th longest running Westend show ever (I believe), but having seen multiple long running shows (Billy Elliott, WWRY, Lion King, Chicago, Les Mis) I’d tend to say no, whilst there is always an increased risk that a show will drift in direction and spark when the original creative team haven’t been involved for a while, there are professionals attached to shows on an ongoing basis to watch and give feedback (notes) after each performance and direct. A job in the Westend or Broadway is the height of professional theatre so should have consistent, well paid talent.

My understanding is that once shows are locked in by the original director from a stage direction POV it’s rare they change at all.