it would be nice if the email handlers (we use Non Quoted Comment Handler FWIW) could remove signatures as they clutter up the comments significantly.

Looking for "-- \n" for example would be a good start as that is the standard and would at least help. I appreciate that flexibility here is probably highly desirable. perhaps if the email consists of:

new stuff

then it's more likely that "new stuff2" is a signature, but you certainly wouldn't want to assume it.