Sweet Charity has a great score, fabulous choreography, a dazzling performance by Verdon or Gallagher or Rivera. The score carries Charity's emotional character arc. Like Pippin and Chicago, Fosse liked flippant endings. It worked in Chicago because it was in a musical number by Kander and Ebb, not a book scene, and it reinforced the superficial and cynical values of society "at that time" but actually a comment on America during Watergate. That end was completely consistent with the entire style of the evening. The last line of Pipiin about being in a musical comedy after such a powerful"suicide temptation" scene with the sets, costumes, and lights disappearing dealt with illusion and reality, and the danger of trying to live in magical thinking and illusions. The one line about it's ok for a musical was flippant, but worse, it undercut the serious theme Fosse had set up. One ending Schwartz has added is Theo singing Corner of the Sky to show the cycle of delusions is about youthful ambitions having to learn to surrender to truth. That works. Another would be for Pippin to sing Corner of the Sky with new lyrics showing he has learned that he is not special or unique, just wonderfully human.
Sweet Charity actually has a comic-tragic ending -- once again, the naive romantic sweet girl has been duped by a user. Reprising Where Am I Going? could have been a good ending musical moment with her dancing off "hopefully" but unsure. But since the book was a cartoon most of the night, very sketch comedy in style, I think Fosse and Simon opted for a cartoon ending, a television "tag." It bothered audiences back then - I remember most of us did not laugh, we sucked in air as if someone had hit us in the stomach. It was a letdown ending, but not for the character, it called attention to the authors and director. It was not a Chaplin "endearing" ending, just a thud.
Anyway, those are my two cents .... I loved Verdon in the original and Chita on tour, even enjoyed Shirley in the movie, and the wonderful score and choreography. The ending never worked for me, either the hippie flower child ending or the other one on the DVD.