The reason I love the potential for this story is just how over Matt can get as a babyface. Ultimately, you're not going to convince anybody in Philadelphia that anyone, much less Matt Hardy, could beat Brock Lesnar for the title on that show. However, what you can convince them of is that Woken Matt is crazy enough to bolieve that he can do it, and his earnest pursuit of what they know to be the impossible would make him an extremely sympathetic babyface. I would even work the crowd's expectations into the storyline.
The story starts with Matt embarking on a Celestial Crusade (the match's tagline but WWE is too PC to use a word like 'crusade') to take his rightful place as the Champion of the Universe, a title that will one day be inherited by King Maxel. Definitely portray it as being done to secure the future of the Hardy clan, because otherwise it would come off as too arrogant. Matt wins a multi-man #1 Contender match on Raw to earn the right to challenge Brock at the Royal Rumble, and the following week is when he runs afoul of the Beast Incarnate.
Brock doesn't have to be a bit player in this story, even though Matt is clearly the star of it. Brock Lesnar should make it clear, with one of his captivatingly autistic interviews, that he doesn't give a shit about King Maxel and that he thinks Matt Hardy is a fucking flake who has no chance of beating him. Lesnar should also insult Matt's legacy in WWE as somebody who's never won a singles World Championship despite being even older than Brock is, the point of this being to make the audience want to see Matt finally win his first world title and to give them more reason to hate Brock for being a smug asshole about it.
In the weeks following, the story follows Matt having disturbing premoneeshuns about his upcoming clash with the Beast. Although his Woken Wisdom tells him that he can win, he also feels that the Fates unknowingly referring to the Higher Power, Meekmahan seem to be working against him. This is to play on the audience's knowledge that Brock is going to retain, and that it will be Roman who wins the title at WrestleMania. Despite these haunting visions, Matt prepares for his match at the Rumble by beating Finn Bálor or someone else credible cleanly on Raw.
For the contract signing on the go home Raw, Matt is accompanied to the ring by his not-yet Woken brother Jeff, who's obviously rooting for his brother to succeed, and V1, his trusted drone comrade. Paul Heyman and Bork come out, and Paul mocks the drone for heel heat and the audience for supporting someone who's clearly insane. In spite of the seal's yammering, the signing goes off mostly without a hitch, although there should be two staredowns: the first between Lesnar and Matt, and the second between Lesnar and Jeff, in case there are plans to give Jeff one last singles title push later. Personally, I think a Roman vs. Jeff feud after WrestleMania could be awesome and do big business for SummerSlam, brother.
At the Rumble itself, I want a fleet of V1s accompanying Matt to the ring for a grand entrance. Sure, that's expensive, logistically difficult and extremely unlikely to happen, but it would be a lot of fun and WWE can offset the costs by selling V1 drones and all of the Woken Matt merch that's going to be sold as a result of this storyline. Matt is unlikely to land a big singles match at WrestleMania anyway, so think of this as his moment to shine on the big stage. Bork comes out and does his usual thing. Maybe give him some damn pyrotechnics this time.
For the match itself, I would book it exactly like Goldberg vs. DDP from Halloween Havoc 1998. The similarities between the Twist of Fate and Diamond Cutter and the Jackhammer and F5 are too obvious for me to ignore. For the finish, Matt falls out of the F5 during the spin and lands on his feet right into a Twist of Fate (what a perfect name for the move given this storyline), but is much too beaten up and fatigued to get the cover in time. There's the painstaking crawl over to Lesnar and the kick out at 2.999999, then Lesnar regains control and hits the F5 to win.
The bad guy wins, but that's just what the Fates had in store for our Woken hero. He comes out looking like a million bucks anyway, and the character that got him so over in TNA that it made fucking IMPACT must-see television gets the spotlight it deserves.
Ahh love it Maggle.