They'd be stupid to cut so much as a line of the Apollo sequence -- it quickly and economically sets up everything that is to follow: in less than 15 minutes it presents all of the characters, their personalities, their motivations and the conflicts between them in an exciting, humorous, lightning fast way. It's cinematically staged narrative shorthand and cutting any of it will result in plot holes later in the show -- Condon couldn't top it if he tried. If anything, if I were director, I might (with the benefit of film editing) add snippets of an act or two more to the talent show, but still maintain all of the tensions of what's going on backstage.
If I were to change anything, it might be the "Heavy" sequence, which is not a great song, but more a useful device to see the escalating tensions within the group. I'd keep the multiple scenes showing the group falling apart, but get Krieger and Eyen to write a better song for it.
I've also always thought that the lyric to "Cadillac Car" was a little clunky and too didactic -- I like the point it makes about the symbolism of the Cadillac and its significance to blacks and Jews, but the song itself isn't great -- I'd want to replace it with something similar in message, but with a more subtle, well-crafted lyric.
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
[http://margochanning.broadwayworld.com/]
"The Devil Be Hittin' Me" -- Whitney