Raymond did a survey on c.l.py, asking anyone who used buffer objects at *all* to speak up. IIRC, he got no replies. On Python-Dev, apart from musing whether they might conceivably use them, the only person who eventually said they actually used them was Marc-Andre. Fredrik pressed for details, but we haven't seen any concrete use cases. In the absence of the latter, it's impossible to guess what would be backward compatible for MAL's purposes.
... Maybe we should do something stronger, and deprecate the buffer type altogether.
I told everyone you forgot the essay you wrote suggesting this the last time this rose above everyone's pain threshold. It's a comfort to know that my channeling powers have not diminished with exponentially advancing age <wink>:
But at least I didn't change my mind. :-)
So let's deprecate buffer(). I also suggest to roll back Raymond's changes to make slices more consistent -- there's no point in changing something that's only kept for backwards compatibility reasons.
--Guido van Rossum (home page: http://www.python.org/%7Eguido/)