Shemp was a poor substitute for Curly. Not as poor as Joe Besser or Curly Joe Dorita, but Shemp was no Curly by any stretch. Shemp was funnier by himself, as in “The Bank Dick”.
Historically, Curley was a subustitute for Shemp first. I used to resent Shemp for not being Curley. That was a mistake. He didn’t try to be Curley nor should he have. He was plenty funny just as he was.
Joe Besser was a disaster.