I think it could work if they built up this big, live two-hour Clash of Chamipons type event that starts on free TV an hour before Mania. You know have this big social media blitz and buy advertising on USA during Smackdown and stuff. You don't build the show around your existing storylines, because you want people to be able to come in not knowing anything about the product. Instead you have someone who's really really good on the mic like MJF come out and run down the audience for 5-10 minutes, put over Saudi, that kind of thing, and then have someone exciting and marketable like Darby come out. He tries to fight MJF, but they are kept apart and that sets up a main event in hour two that's head to head with the lower card at mania.
In between you have all the stuff that's going to sell AEW. You have a hardcore match with weapons and some blood(Nothing too over the top, just something you would have seen in early 2000s WWE with chairs, trash cans and tables and stuff. No pizza cutters or tacks.), you have a spot fest with a ladder or cage, you have a Casino Battle Royale where you parade some old stars people would know out like Jeff Jarrett, Jericho and Edge and Christian, and you build it like Money in the Bank where the winner gets a contract for a world title shot cashable any time, any place. Someone really exciting who actually looks like a fucking wrestler wins, not an old guy, but maybe like a Kenny Omega if he can stay healthy. This is a hook to try and get people watching this who wouldn't usually watch to tune in to AEW to see when the title gets cashed. You pepper a few 2-3 minute squash matches with guys you want to put over in there so the audience has a chance to catch its breath and take a piss.
No Moxley, no death riders, no gay insider storyline bullshit, no back-to-back 30 minute dream matches with no build that exhaust the crowd, just do 10-15 minute matches where you go to the next thing before people get bored. Just quick, punchy attention grabbing stuff.