Madonna improved dramatically for Evita.
I personally don't take much issue with her singing in that film. It's her dead eyes that translate to bad acting is what I didn't like.
But she improved so much, when I first heard "You'll See," I couldn't believe it was her.
She added a vibrato, a controlled one. Something she lacked before when she sang like Minnie Mouse. Her pitch was also much more in control and not all over the place as heard on her many early pop records. The worst one being "Oh, Father."
"Oh, Madonna, you can't sing in tune. Ballads aren't your strongest point, girl" is what a little boy me thought back in the day.
I think she sounds excellent in "Rainbow High," despite her using head voice at the top notes. She really digs into it. Her best number in Evita is the waltz between Eva and Che. Pure musical theatre. She sings it with the needed bite and vocal grit to make it really shine. She is capable, but her problem is she often simply fails to rise to the occasion.
Recreation of original John Cameron orchestration to "On My Own" by yours truly. Click player below to hear.