I've not been shy about my love for this show. As you could guess I think you're wrong about the book and the show as a whole.
I'm glad you enjoyed the extraordinary part that is the songs, I'm sorry you found so little to appreciate in the book and the way it all works together somehow... as I've said here before, I don't know why it worked for me, but it worked beautifully for me or on me. But I don't remember the play being full of cheap melodrama and cliches, let alone trafficking in them (not entirely sure what that means in the context of a musical book).
But you're not the only person, even of people I know and respect, you didn't take to it. I've had a very surprised mix of opinions among friends.
But I almost wrote the show off and missed it.. and I'm glad I didn't.
So I keep telling people to go see it for themselves and see what they think, at worst they'll get the very special concert you refer to.