I'd love to see Austin back in the ring, especially against Punk, but I think there's more chance of Shane O'Mac returning and defeating the Streak...
Austin in any way, shape or form would be a massive plus to any PPV/show, and something I'd like to see. I've never understood why we never see him any more, when Rock / Brock / Piper / Foley / Jericho / etc, are making appearances, some regular, some not so much. We've even had Edge back a couple of times since his retirement.