Several people hit the nail on the head:
It's a small musical that got overproduced and lost in a Broadway house.
The actors were "acting" like children which made the audience cringe.
The music that was added made no sense. It was just inserted so that everyone could have a song, which is not why new material should be inserted. "My New Philosophy", while a cute song, was too modern sounding and didn't fit the rest of the score. "Beethoven Day" was a horrible mess.
And I agree with Jon, Ilana Levine screeched through the part of Lucy. It was painful.
If anyone ever tells you that you put too much Parmesan cheese on your pasta, stop talking to them. You don't need that kind of negativity in your life.