In none of the those renderings was Glinda anything but regal, mature, and Good. Ok, regal and mature and mature are certainly up for debate (I'd say socially conscious and snobbish), but "Good"? In Maguire's book?
I'm re-reading it at the moment, and I fail to see how a pretentious, lying, social climber can be readily described as being "good". Certainly, she was not a BAD person. Her biggest sins did not reach beyond pretense and ego. But when I think of Glinda the Good, I don't think of a person who rebuked anyone who below (or even equal to) her on the social ladder. I don't think of a person who worried only of her social humiliation and never others (as seen when Pfannee wrote the fake letter to Elphaba and signed Galinda's name). I don't think of a person who scoffs at honest offers of friendship and companionship, as she did to poor Boq.
Granted, this is Galinda we are speaking of. I think the name change to Glinda after the death of Dr. Dillimond was a smart move on Maguire's part because it's truly as if she has become another person. But to say she was never anything but good is an overstatement. Mother Teresa was probably never anything other than good (yes, I know she was a real woman, but hear me out!). The character of Galinda/Glinda is certainly one of the more dynamic of the lot, but still, I think it's safer to say she was never bad.
"I'm-Not-That-Boring-Low-Ass-Girl?! You better go up at the end!" - Seth Rudetsky to Julia Murney about her Solo CD choice