The thing that made Ryback's promo work is because it's true. It wasn't the most eloquent, he seemed a little uncomfortable at times, though I don't know if it's because he's not hugely comfortable on the mic yet or because it's something that was difficult for him to talk about. At the same time, however, that made it seem more realistic. It was fairly common knowledge that he suffered a severe ankle injury that kept him out of action for the better part of 2 years. Regardless of from what walk of life you're from, just about everyone likes hearing a story of determination and heart. Ryback was told by several doctors that his career was over and he'd had to overcome a lot of adversity, probably even a good degree of self-doubt, in order to get his career back on track. That's part of why people responded so strongly to Daniel Bryan's promo this past Monday. Fans knew that their support of Bryan genuinely played a big role in his success in 2014, they know he married the gal of his dreams, they know that his dad died suddenly and saw the barely contained emotion that merely mentioning that fact drew out of Bryan. Bryan never even got the chance to say goodbye to his old man, didn't get a chance to be at his side as he just died so suddenly and I think that's something that everyone can relate to in some way. Plus, they knew the issue with his neck was serious and most of them had probably read the same reports over the past 6 months we had concerning the roller coaster ride of different medical information released.
Roman Reigns, to my knowledge, hasn't had to overcome any major adversity. Sure, he had a hernia that kept him out for a few months, I'm not trying to belittle how painful a hernia is, but there was no doubt that Reigns would be back. It's not like he had one doctor after another telling him that he needed to hang up his boots. WWE trying to artificially manufacture some sort of sympathy by having Reigns cut some sort of promo as to how he was uncertain about his career future would probably do more harm than good.
If you don't have something genuinely heart-wrenching to say in order to generate sentiment, it's probably best to not go down that road. I just don't think it's Reigns' time right now, he just hasn't progressed far enough and if Vince believes that most fans want another Superman character, then he's most definitely out of touch.
I think if Roman Reigns' character and his feelings about the SHIELD breaking up when it did were more explored in terms of detail, then and only then, will fans feel that they can understand why they should get behind Roman Reigns.
Roman Reigns doesn't need to do a Ryback promo in terms of going into any Real-life stuff, since as pointed out, he doesn't really have any to truly help him get some 'sympathy'.
However, if we go back to the SHIELD, when they were a group, they moved around as a pack, as close knit, one for all, all for one.
However, when the SHIELD broke up, we saw Dean Ambrose's character explored and got some depth on him and why he was hurt from what Seth Rollins did, alongwith his craziness.
We also got a lowdown on how much of a scumbag Seth Rollins was, and how he truly is a self-serving sell out.
What have we got about the Roman Reigns character exactly?
He went after the Authority, whilst Ambrose went after Rollins in the personal feud which got the fans behind Dean Ambrose big time.
So, we understood that Roman blamed HHH and the other cronies... and up until SummerSlam, the entire angle made sense, and there was some continuity to it, but it all got scrambled thereafter, as Ambrose got written off of TV due to Cinder blocks, with Kane helping Rollins, whilst Reigns was MIA... just imagine if Reigns attempted to at least help Dean Ambrose when he was being brutalised, wouldn't fans have gotten behind him?
For some reason, WWE Creative thought it sensible to have him MIA at times. when instead, acknowledging the Ambreigns alliance would have made sense, they ended up giving the crowd the idea that Roman Reigns was a self-serving guy who forgot his 'brother'.
Yes, he went after Rollins the next week, and beat him cleanly 1 on 1 shortly thereafter, before his injury.
Fast forward to now, and Roman Reigns is now a guy who randomly attacked the Big Slow and is now feuding with him...and has basically forgot what he promised to do in his promo after the SHIELD broke up.
Even in his satellite interviews, he was supposed to go after Seth Rollins, but he comes out to attack the Big Slow? Did that even make sense?
To sum it up;
Roman Reigns has been booked to be the Unstoppable Force in a possible match against the Immovable Object called Brock Lesnar.
But beyond strong booking(Results-wise), there has been a distinct lack of continuity in his storylines/feuds thus far, and especially since he returned from injury, which would have helped tell the fans, he is our guy, get behind him because this is his plight...
They have basically written Roman Reigns in such a way as though he has Amnesia

in order to fast-track him into a match he doesn't have the required momentum for.
Ideally, I assume, had he Not gotten injured, he would have faced HHH at TLC or the Royal Rumble, before winning the Rumble and moving onto Brock Lesnar.
But with injury, instead of applying the brakes, and having him go at HHH like he promised post-SHIELD, they are having him skip that 'blood feud' entirely, to go straight to Lesnar with practically no build and forced booking.
Hopefully, with the Authority back, they will retrace their steps or Reigns' career might end up in reverse gear when it has loads potential provided some patience is shown.