It's not about how good Lesnar acted in the match or how terrible the Miz was, it's about how Cena acted in those matches and this is what both matches have in common. It doesn't matter if the Lesnar match looked more real and brutal, it's about Cena and in both matches the opponent did the work and Cena finished it with 1-2 moves in the end.
Everybody could do Cena's part in the Extreme Rules 2012 match and this is not a joke, trolling or Cena bashing. It was Lesnar who had this aura and the killer instinct who contributed to the brutality but everybody, be it Kane, Riley, Barrett, Edge, Orton or anybody else can play the victim the whole match and finish it with one single punch.
Again, you're over simplifying it. Cena bumped and sold extensively, that's 'work' whether you want to admit it or not. He bumped and made himself look in peril and his presence added to the match. The adults took glee in seeing him get bloodied and smashed with ungodly stiff Lesnar strikes and the kids begged him to make a comeback. Most babyfaces do less work than a heel in terms of controlling a match. The face has to sell and bump and do a lot of work without doing much in terms of offence. He'll get a shine period and a comeback, everything in between is the heel controlling. If you can't see the difference between a terrible Cena/Miz match where there was no heat, no compelling performance or smart work with that of Lesnar/Cena where the entire match built and built and built to the Cena comeback where the monster Lesnar was finally troubled...then I can't help you. Cena/Miz was a basic match done in lazy fashion and lacking in any charm. Lesnar/Cena was how to work basic but add enough subtle and intricate touches in pacing, selling and build to make it matter in the grand scheme.
And again, if you think Alex Riley could control a crowd and make them give a shit in the manner Cena did (whether it was positive or negative) you're blind. Cena has a connection with all the folk in the audience of any dynamic, he bumped in a way that others could but no-one else on the roster minus Taker and Punk (being a Chicago crowd) would have generated the buzz and intrigue like Cena did, that is the crucial difference.
Your argument implies Barrett could work a Jerry Lawler match as good as Jerry Lawler, if he merely copied and recycled Lawler's offence, since Lawler didn't do anything 100 other guys couldn't do in terms of the offence he used. That's woefully naive on account of things Lawler could to make his matches so great in spite of working with a limited offence and moveset.