It's down to me manually taking the diff and putting it into the Pynac upgrade trac ticket but yes, everything up to that point can happen on github.
You are right but I have a habit of doing thematic commits which makes reviewing easier. Also cuts down on merge commits. OTOH authorship is lost on the Sage changes. That would be an argument. I'd like to hear the opinion of the long-time reviewers like Jeroen or Karl-Dieter on this. Are commit message and structure important for review, or do you just skim the diff?