"The understudys in the LA cast (Emily, and Julie) won't be assuming the roles once they left. The LA company wants to keep people who are a "name" in the community of wicked playing the parts...so tickets will keep being sold. They will likely fill in for awhile if no one has yet to have been cast, but don't look for a full headlining gig to be coming their way. Especially because Julie may be leaving again to go back to a different OZ."
I disagree with your assessment of the production team wanting to keep "names" in the part to keep ticket sales up. People don't come to "Wicked" to see whose playing Elphaba or Glinda; they fill those seats to see the juggernaut that is the show, regardless of whose in it.
The producers have proven
very prone to promoting standby's and understudies to lead roles and have done so in every single company so far (Shoshana Bean, Eden Espinosa, Victoria Matlock, Erin Mackey, Dee Roscioli, Kristy Cates, Derrick Williams, and Kris Cussick just to name a few.) I see no reason why they'd suddenly change their casting philosophy, especially when it has worked so well in the past.
Any time a new talent is hired even in the standby variety (like they've been doing lately) it is a suprise. While I think some new faces in these roles would do the show good, the company just feels more confident in people they've already had prove able to maintain the show (hence the constant recycling.)
Tonya Pinkins: Then we had a "Lot's Wife" last June that was my personal favorite. I'm still trying to get them to let me sing it at some performance where we get to sing an excerpt that's gone.
Tony Kushner: You can sing it at my funeral.