The original was cast brilliantly. Not easy to do. Borle is ABSOUTELY more of Mendel. Marvin is more like a Younger Raul Esparza, like when he did Company. He needs to be complicated and a bit edgy, more typical tall dark and handsome. That's not Borle.
Rannells is also just not right for Whizzer. Whizzer is supposed to be unaffected, a regular guy, not camp. His song at the end, You Gotta Die Sometime is a take on Operatic Tragedy. Rannells voice is wrong ..Rannells is all camp. This casting is potentially what could make this revival a failure.
Block as Trina is the best of the three at least. She will sing this exactly the way it should be sung. What she lacks as actress she makes up for in song interpretation and the show is almost entire sung through.
Lisa Howard would be a perfect Dr. Charlotte. Her type is a nod do Heather MacRea and she is quite possibly the best Will Finn interpereter out there.
Cordelia is a tough one...she needs to be funny and quirky but believable. Annaleigh Ashford would be fun, leslie kritzer (toned down) Kerry Butler (she'll have to go for more nuanced.
I think James Lapine is the wrong choice to helm this in 2016. He is a decent director, a better designer, but he's dated and I'm not sure he's going to investigate this piece the way it needs to be investigated now.