To say it "didn't work the first time" is to buy into the myth that the show wasn't a success. It ran 15 months and while it was a financial failure - and true many in the mainstream middle-aged Broadway audience were put off bu the dark aspects of the show - the book was very effective.
If there is a flaw - and I am not really convinced there is - it is the fact that the 4 main characters learn nothing from the "Follies" segment. The changes to the ending tried to address this but could never find the right tone. The despair and hopelessness ending was what left many with a sour taste, but it was the most honest. And I for one would rather deal with that than any attempt to make it a "happy ending."
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com