To me, any evaluation on punk/austin is way too premature in the here and now. In all honesty I'm not too big a fan of the current wrestling product as a whole, currently. There are a few bright spots, and cm is absolutely one of them. He's solid in all factors (ring ability, promos, drawing heat/cheers when needed).. But time will tell if he's on Austin's level.
You've got to consider.. Punk is still somewhat new in the main event spot. Austin in a sense sparked the attitude era, and wwf's eventual stomping of the wcw brand. Punk isn't even in the same breath as Austin, now. Eventually he may be. But the thought of him being there in this time is ridiculous. There are few superstars rated as the best of all time (ric flair, shawn michaels, undertaker, bret hart, hulk hogan, the rock, etc) and Austin is among them. CM has many, many, years to come. It's not fair to compare them yet.
In ring ability- goes to Punk as his background/style is much more of a wrestling caliber. Austin was much more of a brawler, but could pull wrestling maneuvers out of his bag when needed (remember his fued with benoit?) But that stone cold stunner cold come out of nowhere, and I've never heard a pop like it use to get..
Promo work - New era might give it to punk.. But Austin wins in my book. Austin always ad-libbed his work.. Not saying punk doesn't as well.. But Austin's ability to be neutral over the years, and make you forget you were watching a scripted wrestling program was something to marvel at.
Would I be for a match between the two? The set-up is perfect. But.. It may be a few years late... Austin is my favorite wrestler of all time (trailed closely by hbk) but I know how he's limited to what he can do in the ring now... And honestly his whole "sheriff austin/half-stunnering people gimmick wore thin for me.