I want to add my voice to the chorus of those who love Audra in this role. I think she is completely devastating, but also sexy, vivacious, and yes, manic at times. But I've never seen her go into full-blown hysterics, nor have I felt she was "acting" at all. Her voice is thrilling on this score to me. But I think the thing I am most impressed by is how truly maternal her Rose is - in my opinion, this is the most maternal I have ever seen Rose played. Which is all the more disturbing when she offers Louise up to strip.
And, for what it's worth, Montego Glover's Witch in Into the Woods destroyed me, so I'm very excited to catch her Rose as well. In no world was Heather Headley ever doing this. And any assumption that Audra "stopped" her from doing it is weird.