They were trying to push him as a "powerhouse" in the same way they tried to do with HHH a few times over the years. They'd have Reigns do a few minor feats of strength here and there but have the announce team play it up as some impossible feat they'd never seen before.
Well it's what they're doing with Braun now, and you know it's most likely to give him some cred to book a feud with Lesnar or Taker. Not to mention, Kane and Big Show should be hanging it up in the next couple of years, and if Triple H is being allowed to have some influence, you know he's trying to help build a monster for the next few years. Other than those three, the biggest guy they have is Mark Henry, but he's much shorter and more aged.
Kind of like when he'd lift sheamus off the ground but it would take a very long time for him to do it and he wouldn't get him that high but the announcers would sell it like its the greatest thing ever, yet Brock could do it easily and better looking. I do wish his power moves were better, and i actually like the superman punch, but it comes off really stupid when he hits Brock with it and Brock sells it like Luke Cage being shotgunned in the face.
As far as Brock is concerned, I don't know if they have purposely booked him like this, but I've noticed that he tends to get beat up more when he's in a match longer, and I thought they should have played that up some more. Like realistically, Reigns shouldn't be able to beat Lesnar today, but it would make much more sense if Reigns was built up like Rocky, where he could take a beating and eventually outlast an opponent like Brock, who just become so tired out after 20 mins that he's more weakened.
But yeah, I've seen Reigns fail to lift a punch of guys like that, and maybe it's because he's doing it one handed, but it's a real big difference when you see someone like Cena catch a guy of the top rope, fall and get bad up and reverse it into an AA. I don't know if Reigns just doesn't have that kind of physical strength, he does need some more power moves.