Tournament on RAW and Smackdown Live. All upper-card men on both shows. Winner goes on to rep the show in a four-way elimination match against Brock - call it a call-to-arms of everyone in the promotion to recover the Universal Title back, with the guarantee that whoever wins that will co-main WM.
You now have a chance to run a series of matches every show on both main shows built around this - but also very intensely tied to the 'wins and losses' matter statement being revived and months being invested in making this a legitimate thing. Because this isn't a standard round-robin. This is points-based, G1 style, and all matches will count for it, including ones that occur on Main Event, ones that happen on house shows. Ones that happen on 205 live. Leading to a lot of people who might otherwise not get TV time being able to be included, but also perhaps leading to people watching those other shows. Flash-finishes, sudden alliances, the like start spreading out like wildfire.
And, in the interest of making sure that the developmental situation is represented, and to give those down in NXT a big opportunity, (and to the minds of fans, elevate someone to that upper level but also give an easy first elimination) a similar tournament happens down in NXT.
Dragging along, with people popping up high in the rankings, teams like New Day sacrificing for the good of one of their own even if it sets back the other two - them getting Kofi a title shot could be a running storyline, up to and including them subbing themselves out of matches for him to get him points - it all building up until you end up with your winner from RAW, Smackdown, and NXT.
Given enough time, anyone could be in these roles. Bryan would have been fighting hard to win that out of a desire to unify the titles and have even less superfluous leather, we all know how the egos on RAW work, yadda yadda, but really it could be anyone in these three slots.
Start the match, and they all immediately beat Brock down, pile on, and he's eliminated. Gone. Now you have an entire match of these three that you have spent, hopefully, the last couple of months building up on their individual brands all here to put on a showcase. Double points if the person who actually gets the pin/does the final finisher on Brock if whoever is from NXT, because that's a damn good way to give them some first-look shine from people who only watch main roster. (Dream dropping that elbow and that being the nail that puts Brock down would be wonderful)
Whoever wins ends up on RAW with that stupid red belt, and it doesn't much matter who,
But you let people feel like wins and losses matter over a series of months. They will be checking online if its done right to see what was going on at house shows. Can let people cheer their favorites without feeling like you need to torpedo them for the sake of someone you're trying to push, and can even use the final numbers from the individual brands to determine where people are on the card going forward.
It gets Brock out of there in a way that makes him seem like he needs to be teamed up on to beat - in case he wants to come back and give a shyt - but it also implies prestige if the whole company is willing to basically jump into this to win the belt he's been holding off TV so much it doesn't seem worth a shyt. And in the process, hopefully you build up a new top guy on each brand, bring up someone from NXT with immediate attention from their showcase in the final match, and you got a whole bunch of people some wins in a new environment where wins and losses matter more than how much the eleventeen authority figures like you.
tl;dr: Basically WWE runs the G1. Almost literally. It'd be better than anything else they're doing.