Ric Flair versus CM Punk seems plausible. They kinda jump started something back in December/January between them (or maybe reports just said they were about to) that never got a pay off. Some people even believed reports that they might face at Elimination Chamber. I had a good laugh at those people (no offense if you are one of those people, gentle reader.) Could work as part of the build towards Punk vowing to end the streak, by attacking another legend who himself failed to kill the streak (a brawl, not an actual match. WWE won't let him wrestle again, thankfully.)
Another possibility is getting destroyed by Lesnar as part of the build towards HHH/Brock. Don't forget about much Triple H respects and worships Flair and thus how hard he'd take it if Brock completely destroyed him.
Don't see him doing both.