Okay, I've never written a review on here before, and am not that up to date with the cast details and such, but here are my thoughts.

Carmen Cusak is awesome. I loved her in clips I'd seen, but I wasn't expecting her voice and acting to be as powerful as it was. Her constant tendency to do things like the MGM movie Witch was awesome (a laugh here, a wave of the arm there). Her "Defying Gravity" was a powerhouse that had me in tears. Same for "No Good Deed." I ADORE the way she says "wicked" at the end of ALAYM.
The Glinda was over the top wonderful. "Popular" was divine, with her falling all over the place, and I really loved how powerful her voice was, too, and how clearly you could hear everything she sang in any kind of voice. The two and their voices work perfectly together for "For Good..."
Fiyero is gorgeous, and really, really good. He's perfect for the dancing through life Fiyero and the Fiyero at the end, and everything in between.
Nessa was, quite frankly, the best I've seen. So vulnerable, and the way she morphs into such a powerhouse during WWotE is amazing.
Great cast they have going for them!

Who was on as Morrible?

Great review! Carmen is by far the best Elphaba; such a powerhouse!

Was Katie on as Glinda?

^According to a review on the BroadwayWorld boards she was on:
http://www.broadwayworld.com/board/readmes...5&boardid=1

Yay, I'm glad she's back.

What happened to her?

She was on vocal rest.

ETA: According to someone on BWW, Alma is still Morrible.