iluvtheatretrash, I'm with you in the Glenn Close camp.
And when i mean camp, I mean it in every sense of the word.
While I only have the LuPone cast recording to go by, I found her kinda one note and listless on the recording (I also found Kevin Anderson's Joe kinda the same way, though I love his voice more than Alan Campbell's). She's been sounding like a Patti drone for her last few recordings, and she's missing that extra "zing" that her "Evita" and "Anything Goes" recordings have.
Glenn Close, while I admit is not the greatest singer, I thought was great in the role on record (again, I didn't see her live). I think the point of Norma is that she's not supposed to be all that nuanced vocally, as she was a SILENT screen star, and thus is supposed to be prone to over the top, larger than life gestures, and the reason why she got kicked to the curb in the movie biz was because audience tastes have changed, or that she doesn't have a really good voice for the movies. She also really brought out the "campy" elements of the show, which lightened up what other wise is a pretty dark and dour show.
I agree that Diahann Caroll (whom I did see) was good at Norma, and I liked her interpretation. She seemed to bring a regalness to the role in her interpretation, where she is a grand dame that is past her prime, but you can see what once made her grand, and it's even more heartbreaking that she is trying to relive her glory days.
I also saw Petula Clark in the stripped down touring production, and I thought she was too campy (I know that I just put that down as a plus for Glenn Close, but there is a line I have to draw somewhere).
And don't forget that Patti wasn't the only one screwed over in the Sunset debocle. Fay Dunaway (who I would have loved to see try her hand at Norma) was also pushed aside because of Glenn when she was supposed to take over the LA production when Glenn moved to Broadway, but then Webber decided to close up shop in LA instead, leading to another breach of contract lawsuit. I think if those two lawsuits didn't happen, "Sunset" might have recouped itself, or at least not be so far in the hole when it closed, though it was an expensive production to run.
Xanadu! Can't cry on cue!