On topic, I think Sara would be perfect, but I also pictured Debra Monk when they first started talking about bringing the show.
Off the main topic, but commenting on an earlier discussion because, darn it... it's Sara. :)
Sara Ramirez has said that she fully intends to come back to Broadway at some point. She bought a home in LA and does have a contract with Grey's, but that doesn't really mean anything concrete. They can be written out or choose to go.
And while she did have terrible throat problems during Spamalot, it was her first role of that size and it is quite demanding vocally. I don't know that she would ever take such a demanding role again.
Pretty pretty please don't you ever ever feel like you're less than
f**ckin' perfect!