If it comes down to them returning around the same time and the result being that the spotlight winds up being taken off of one of them, I think Reigns is in trouble. Even though some WWE officials might want Reigns to be the next guy, he's still a VERY, VERY long ways off from being at that level. When it comes to fan interest and response, the simple fact of the matter is that Roman Reigns isn't remotely close to Daniel Bryan's level. As a result, I'd be extremely surprised if fans didn't rally around Bryan and want to see him pushed instead of Reigns. There are some fans who're already turning on Reigns because of reports that he's someone that management really likes. What that means is that, in the minds of some of those fans, Reigns has a better physical look, the kind of look that Vince prefers, and will want him pushed ahead of others who said fans might not only like more, but who feel are just much better and more talented than Roman Reigns. I'm not saying that to hate on Reigns, I'm a fan of Reigns and have been since the earliest days of The Shield, but facts are facts. Reigns' popularity isn't anywhere near Daniel Bryan's level and Reigns, as of right now, is going to have to develop quite a bit over the next 6 months before I buy into him as an interesting and legit challenger for the WWE World Heavyweight Championship.
If WWE officials wanted to badly enough, they could completely ignore the interest and wishes of fans and demote Bryan down the card by booking him to look bad week in and week out. Eventually, even the hardest of hardcore fans will get tired of hoping, wishing and wanting WWE to push Bryan; they'll realize that it's a futile effort and move on. The problem, however, is that there's absolutely ZERO logical reason to do this. Bryan's very well liked and respected by producers, key members of WWE management and the other wrestlers in the locker room, both male and female. He's reportedly known as a pro's pro who conducts himself like a pro, treats everyone well, never acts like he's above anyone else. An example of how much of a pro Bryan is was when he stayed on Raw, despite being obviously shaken up and barely holding himself together emotionally, to do the segment with Kane on Raw just hours after learning that his father suddenly passed away. He's among the top in-ring wrestlers in the world today and really has been for the better part of a decade. Segments & matches centered around Bryan from post SummerSlam all the way up until his injury were almost always the most watched portions of Raw or SmackDown!. Bryan's merchandise is second only to Cena's in terms of sales. Fans both WANT to and LIKE cheering for Daniel Bryan. They tried turning him heel early this year and we all saw how that went down. Bryan's something of a rare breed these days in that he's someone that pretty much everyone across the board likes to openly cheer for. Men, women, kids, average fans, hardcore internet fans and everyone else in between enjoy cheering for Daniel Bryan as a face. As with any wrestler, not everyone is a fan of the guy, but that's just how it is. There's probably no single wrestler to come along to the WWE roster in years that's as close to being universally over as Daniel Bryan. As a result of all this, and these are facts, there's no reason for Bryan to be pushed down the card because there's absolutely no reason for him to be pushed down the card. If he flunked the WWE Wellness Policy, if he behaved like an asshole backstage, there'd be genuine cause for him to be punished by being buried. If Bryan didn't draw ratings and make a lot of money for the company, there'd be justification in his push being killed and being pushed down the card. I mean....it goes completely against all forms of logic to punish an employee for doing exactly what you want and hope he can do.
As none of those things have happened and no one has come remotely close to Bryan's popularity in his absence, including Ambrose & Reigns, there's no reason to believe Bryan's popularity has faded.