BSO: Are you truly serious?
A white woman ABSOLUTELY CANNOT portray AIDA without some of the story's integrity being lost, if you don't understand that then there's no reason to continue with this conversation.
A more than qualified white woman could ABSOLUTELY portray Dorothy in THE WIZ. THE WIZ is not a show about race. It's always been done that way, but there's nothing in the show that limits the cast to being black.
And no, once again, A WHITE WOMAN CANNOT PLAY CAROLINE. The show, if you had seen it, is obviously about race and the african-american struggle in the 1960's. Caroline is a black maid in a white house which is ABSOLUTELY necessary to the story. If you, again, do not understand that, then I feel truly sorry for you. The role of a black maid cannot be played by a white woman when the show is about her and her family.
And, you're wrong again. A black man could not play Tevye, as Tevye is a gender and race-specific role. Glinda is not, so your analogies once again fail. If you're saying a black man could play Tevye, that's like saying a white woman could play Tevye. It is not within the boundaries of what the role must be. That would be like you suggesting a production of A RAISIN IN THE SUN with a white family - it will not work and it was not intended to work. However, a play like ON GOLDEN POND, which has always been done with a white cast is being revived on Broadway with an African American cast. Will it work? Absolutely. The characters are not race-specific and the story is not about overcoming racial issues. So unlike CAROLINE, AIDA, and RAISIN, ON GOLDEN POND (like WICKED) can be done with a cast of any race.
"If you are going to do something, do it well. And leave something witchy."
-Charlie Manson