I think there has been some discussion of signals, in the last year, on the py-dev list (== gmane.comp.python.devel), which is archived both on the python site and gmane.org. Signals seem to be a somewhat nasty subject.

Since you only raise a question rather than proposing a specific, possible change, I am closing this for now. I suggest you open a discussion on python-list (mirrored as newsgroup gmane.comp.python.general). Perhaps a specific proposal would come from that, perhaps you would find that your idea is impossible.