I love Pamela in full, but I can't stand Pam or Pammy. I did spot one baby Pamela online somewhere called Mela/Mel, and I like that much more. Fear of Pammy or Pam, though, would probably keep me from considering the name.
There are a lot of names from Pamela's heyday that I love only in their full forms, without nicknames, such as Deborah, Judith, Cynthia, and Susan.
Names from the 40s, 50s, and 60s, including Pamela, are in the early stages of revival, imo, but do still feel dated.