To provide feedback on this draft join the atom-protocol mailing list.
Rather than trying to keep up to date on all the activity in the Atom WG, I'll just send you over to look at the nice Atompub Status Pages that the IETF is now generating.
The previous version of the draft RFCs are available:09 08 07 06 05 04 03 02 01
See Deconstructing the AtomAPI for the discussion that lead to the large changes in the rev 08 of the Atom API.
Extending the AtomAPI is an write-up of how to use namespaces to extend the Atom API. The example is for the pre-08 version so of the API, but the principles apply just the same.
This file last modified 2014-11-30.