I'm not sure RSS vs. Atom is a good comparison. As far I understood it, Atom was created to address the limitations in RSS with a fresh approach, not simply to further refine behavior in a loosely specified format.
And while I'm aware he wants them to do their thing with a new name (an argument I can agree with for sure), I think he'd probably still complain about a connective name (e.g., Sparkdown). I don't know for sure, but given his posture to this whole thing throughout the process, it seems likely. At that point, though, I think they could justifiably just give him the proverbial finger. :)
EDIT: Turns out I was wrong. He gave them a list of similar names (with Markdown in them no less!) in a recent e-mail.