Is there a way without editing the default maildrop to provide user based drop scores? Or is it currently just per domain?
Depends what you mean by user based drop scores, but per-user maildrop scripts are available, the catch is the server administrator has to create them, there’s no web interface, etc. The default maildrop script looks for
per-user mail drop scripts, and includes them if they exist. In that example it would be for the postmaster@domain e-mail user.