After watching Payback, I started thinking about Reigns. I know it's just a matter of time before he's champ because WWE are waiting for the crowds to accept him. But, if John Cena has taught us anything, it's that the Smark contingent will change it's mind about a wrestler. Once you're a heel/face, in their eyes, it doesn't matter how well you're work or how well you're booked, you'll always be their first impression of you. So by that logic, Reigns will never be "ready."
But, if all that is true, why the heck does Reigns even need the title? Why not just make whatever match he's in the main event, regardless of what's at stake. In other words, make him the John Cena Champion. You could even christen this new era by having him beat Cena in a main event, while Rollins fight whomever. As you said, the title is not the title. As an added benefit, if Smarks start seeing Reigns fighting, and winning, in the main event enough, they might even became resigned the fact that, ehhh, who cares. Might as well make him champion. At this point, that's the best you can hope for, I think, with Reigns.
I suppose they could always build up to him finally being the guy to win the John Cena Open Challenge, too. But yes, in general if you start treating a guy like a main eventer, eventually fans will accept him as a main eventer. Sometimes you just have to do it like HHH in 2000 and completely sacrifice a guy to get there, but it's generally do-able. It's still a problem that Reigns is getting title shots and not winning, but at least fan support for him is becoming a tad more organic now without Bryan around.