Maybe on SmackDown, but I don't see him carrying RAW. Which is what you do if you're the champion, you're relied upon for viewers/ratings. Ryder is over with smarks, and casually getting over with some casuals, but is that enough to carry RAW? Sure, Cena/Lesnar is something to full back on, but Punk is over with everyone and is stuck on the first hour most of the time, so I don't see someone like Ryder being the guy.
Where as SmackDown they don't care - they can test whatever they went over there and it wouldn't surprise me to see WOO WOO WOO the WHC.