WWE has botched the first month of Sheamus's reign quite badly in terms of capitalizing on how over he was and how much the audience was behind him pre-Wrestlemania. Bryan's surge in popularity, the "YES!"-mania, the large segment of the audience that was turned off by the 18 seconds incident, the shoddy way they book the World Heavyweight Championship on Smackdown in general, the lack of promo time/character development for Sheamus... It's all conspired to harm him. His stock has actually gone down after winning the championship and Bryan's has curiously skyrocketed since losing it.
However, if there's a brain to be found backstage in WWE, they can invent a way out of this. (Cue Jimi Hendrix's "All Along the Watchtower.") Let Bryan and Sheamus open Extreme Rules up with 30 minutes to tear the house down with. Bryan just ever-so-narrowly loses, earning Sheamus's respect because he didn't "hide behind AJ" or whatever, Sheamus offers him his hand and Bryan accepts, shaking it. Having Bryan as the top heel on Smackdown isn't going to work when they're in smart mark cities and he's cheered, or even receiving split-to-largely-positive reactions as he has in at least a couple of non-smart mark cities now. Then trade Miz to Smackdown and build him up for a month or two as the smarmy asshole he's so good at being, taking cheapshots at Sheamus at every opportunity, etceteras. Once Sheamus has barely withstood Miz for a month or two, have Del Rio feud with him for a solid month, issuing a bounty on the head of Sheamus for the entire Smackdown roster. Every heel on the brand is going after Sheamus at this point. Well-earned sympathy for your babyface isn't a bad idea. Having him encounter and persevere in the face of overwhelming odds helps your face. Making him indestructible and invulnerable typically doesn't. Once you reach the road to Summerslam, I'd commence Mark Henry's retirement angle, which is a nearly four-month feud with Sheamus for the championship, concluding at Hell in a Cell in an almost brutally barbaric match.
Meanwhile, keep Bryan going strong as the brand's #2 face (I think Orton's Raw-bound this summer), and then after Sheamus has a monster reign that concludes at Survivor Series, have him drop the championship to a resurgent Wade Barrett coming off from his injury time off with a revitalized character and presentation (and new theme, for God's sakes). Bryan continues being built as the plucky "Yes!" babyface of the brand, who fights his way, one way or the other, to challenge Barrett at Wrestlemania XXIX. They could hype and play up their shared history dating all the way back to NXT 1, three entire years earlier, and contrast them from one another. The heat for a Bryan/Barrett match at Wrestlemania, with so many English fans and so many smart marks who worship Bryan, could be positively immense with the proper booking and build going into it.