Actually Austin is too smart.Nobody would go over Austin in a feud ever. He's just too prideful (almost Hogan like) for that.
Only reason Rock went over him at WM 19 was to compensate for all the time Austin had buried his (candy) ass in their past feuds. Austin won 3 feuds over him to be precise before their WM 19 program.
Plus I don't think Punk/Austin will ever happen unless one of them turns heel. Them trying hard to one up each other on the mic just by being a smart ass week in week out, which is how I envision a face Punk face Austin feud would be, will get repetitive too quickly.