Wrestlemania sells almost entirely on brand name no matter what the actual card is (hence why most tickets are already sold months before a single match is even announced), so the show will be a guaranteed success either way. However, when it comes to breaking the all-time attendance record, it ain't happening. Just ain't happening. I don't even think they stand much chance of breaking their own supposed 93,000 record from WM 3. They'd need something really special like the return of Stone Cold and/or a high-profile celebrity in a really hot angle that captured the attention and imagination of the public, and even then it's doubtful they'll sell the number of tickets they want to.
In either case, the uncertainty as to what we'll end up getting is at least making this an interesting Road To Mania to say the least:
Reigns/HHH is obvious unless Rock gets the clearance to wrestle, then it becomes Rock/HHH and Reigns/Lesnar. Rock/Lesnar is easily the biggest match they could do, but it has such small chance of happening that I won't even seriously consider it.
We know The Undertaker will be there and there's the lingering question of whether this year could be his swan song or not (I doubt it will be.) If it is, that opens up a couple interesting possibilities, especially with Cena . Maybe he'll put over Bray Wyatt and officially christen him as "The New Phenom/Face Of Fear." Maybe he'll work with Kevin Owens and let KO beat him instead. Or maybe they'll resort back to one last program with Brock Lesnar and have The Beast retire him once and for all (or conversely, have him finally score a victory over Lesnar and finally ride off into the sunset with his head held high after finally conquering his greatest foe.)
As far as Brock is concerned, if he isn't working Reigns, then it's either Kevin Owens, Bray Wyatt, or the aforementioned fourth (technically seventh, but who's counting) and final encounter with The Dead Man. I thought over a month ago that Sheamus may have even been a slight possibility, but he's jobbed to Reigns so many times in a row now and even just lost to Brock himself on a house show that I struggle to think what the point would be.