Great article about the character arc of John Cena and the WWE, I really enjoyed it and you may as well:
http://www.grantland.com/story/_/id/7904055/why-john-cena-losing-rock-brock-lesnar-matters-wwe
Good viewpoints.
Yeah, good point on how they effectively made Cena into the underdog going into Extreme Rules, but I think that, after the hilariously one-sided Kane feud, it was only by virtue of how implausible Brock losing in his first match back sounded, and how much that flew in the face of what the fans could see as logical booking for a presumed impending Brock/Cena feud. That awful post-match Cena promo, and the carny-as-fuck 'snapping' of HHH's arm has, for me, undone any good work they achieved with that match.
Also, I can't agree that it was a "triumph of narrative, not for Cena the wrestler, but for Cena the character", because it seems to me that it's back to business as usual for John Cena. Just like when a despondent, defeated Cena closed the show at WrestleMania, only to turn up on RAW the next night, yucking it up like nothing had happened, nothing's changed here, certainly nothing lasting or long-term.
He put everything on beating Rock in the build-up to Mania, yet the only way his loss factored into it was to cast doubts on his ability to beat Brock. His character hadn't changed in the slightest. He seemed legitimately shaken and intimidated after Brock busted him open on RAW, yet in the end he beat the odds and came out of it smiling. I see no narrative for Cena the character here, other than the same old, same old narrative of the odds being stacked against Cena for him to overcome.