It's nothing against Reigns personally, and some people have incorrectly tried to argue that fans are fickle for cheering him in the Rumble last year, then booing him this year. But that completely misses the point.
People cheered Reigns last year, because he was the last alternative to the guy they were trying to obviously ram down our throats as the returning good guy last year, Batista. And The Shield was very over at the time, despite being a heel faction, and it would have been a pleasant surprise to see someone like that win it. But he still wouldn't have been ready for a push.
Fast forward a year, and the Shield have split up, and Reigns has had a total of one singles match against Orton before getting injured, and it sucked. He's clearly not ready for a 20-30 minute singles match. On top of that, since returning he has had a string of embarrassingly bad promos that have shown that he's not ready on the mic either, and have been a major WTF.
In the meantime, Ambrose and Rollins have worked their asses off and become potential stars, good on the mic, good in the ring, and get a response from the crowd. But from the moment The Shield split up, the plan was always for Reigns to be the next top guy, and they've stuck to it despite him being out with injuries for the better part of the year, and despite his total lack of progress in any regard. This is the sign of a company that doesn't adapt or evolve or listen to fans. They live in a bubble. They made up their minds at the time, and they haven't taken note of what's happened since.
And they've shunned Bryan with the excuse that he's not a top guy due to getting injured. Because their biggest star of all time Steve Austin was never out for the same amount of time with a career threatening neck injury. HHH was never out twice for a quad injury. Nope, top guys don't get injuries.
You'd have to be allergic to making money to overlook the most over guy in the company in the past decade, especially when their chosen top guy of the past decade, Cena, hasn't been without boos for the better part of that time. It was unanimous booing at the Rumble match, too.
And the RR match had a ton of deserving people get treated like total crap to make Reigns look as good as possible. Bryan gets booted out as early as possible because they knew the fans wouldn't be happy about it, yet they did it anyway. Ziggler gets the #30 spot, not to give him a good opportunity in the final moments of the Rumble, but to give him as little time as possible in the ring, and for him to get tossed out two minutes later literally like a piece of garbage by Big Show and Kane, same with Wyatt (even though I think nothing of him, but at least he got a good run), and Cesaro. It's frustrating as a fan to see the company time and time again overlook so many talented guys that the fans love, all because WWE doesn't care who the fans like, they want to continue to try to tell us who we like, and treat potential moneymakers like crap because of petty personal vendettas. This is not what's "best for business" at all.
People turned on this Rumble not just because the wrong guy won, but because the rest of the Rumble match suffered so greatly and obviously to make it happen. It was entirely booked knowing the fans wouldn't be happy about any of it, and trying to minimize the damage so they could stubbornly stick to what they wanted, instead of what the fans wanted. That doesn't mean you always have to give the fans exactly what they want by any means, but at least don't spit in their faces in the process. Bryan's WM win was all the sweeter for fans last year because he had to fight for it, instead of just instantly making him champion like fans wanted. WWE were lucky they managed to turn that around, but they should always have a greater plan that takes into account what the fans want to see.
This Rumble insulted the intelligence of the fans by thinking we'd have the memory span of a goldfish after Bryan's elimination, and cheer once they dangled their chosen one in front of us. Then as damage control, they thought they could simply transfer The Rock's heat onto Roman Reigns just because they get buddy buddy in the ring. How easily manipulated do they think the fans are?
They brought this on themselves two years in a row by not respecting their audience, resulting in twice the RR match has been a trainwreck to the point of being newsworthy. This is not good publicity for WWE, and like last year, they'll need to do better to avoid a disaster at WM.