Not nearly as good as Hogan's turn, but still good.
To really put Cody over now they need to have Cena + Rock just beat the everliving shit out of him at WM, "steal" the title, and the buildup to him winning it back at SummerSlam with a surprise "help" from somebody like Stone Cold, HHH, etc.
I don't know that Cena/Rock have that many appearances left on their contract though. So, they'll likely go the boring route where Cena loses to some intervention by Seth or something, setting up a Seth/Cody showdown of, "That's twice! You owe me!" angle from Seth.