Usually before a studio will commit to casting an "unknown" which outside of the theatre world, Idina & Kristin are unknowns, they would like them to be seen on screen at least in supporting roles so the public can at least have some idea of who they are, even if they can't remember their name. This is true with PHANTOM, also. Emmy Rossum was just seen as Sean Penn's daughter in MYSTIC RIVER and as
<--------------------'s girlfriend in THE DAY AFTER TOMORROW. Most people will not remember her name right now, but her involvement with those films is enough along with Webber's name and the name PHANTOM to bring some people in.
Now that Kristin is involved with several HUGE pictures coming up and Idina will be soon be seen on the big screen the chances for both of them being cast increases not to mention the sheer number of CD's the cast recording has sold. However the supporting roles will require real box office names. Don't think that Carole Shelley & Butz will reprise them for the screen. But there are so many musicals being kicked around right now as possibilities for production and WICKED is one of the most popular musicals in a very long time, so a big screen version might not be as far off as some people think.
"Noah, someday we'll talk again. But there's things we'll never say. That sorrow deep inside you. It inside me, too. And it never go away. You be okay. You'll learn how to lose things..."