timezone is relatively new.  Work is in progress to add better timezone support to datetime, but it is a complicated subject and may or may not make it into 3.6.  In any case I think it is too soon to talk about this kind of API change, before the other work gets farther along.  That's probably also true for changes to the docs, although a concrete proposal there might have some chance.

There's a mailing list for talking specifically about datetime issues, you might want to post there (see mail.python.org, datetime-sig).