Re: John Cena's WrestleMania Opponent
If Samoa Joe were a heel, I was thinking they could build him up on a monster run from now to then, and have him be the annual monster heel that Cena squashes at Wrestlemania, much like he did to Rusev this year and Bray Wyatt last year. But Joe isn't a heel, and I think they'll want Cena in a much more marquee match come next year considering they want it to be the biggest Wrestlemania ever and he is still the face of the brand.
What about Cena vs Sting? My interest level in that is pretty much zero, and what I'm about to type isn't very likely at all, but what if they had Sting win the WWE Championship at Night Of Champions, keep it until Wrestlemania 32 (with him only wrestling on PPV's, and maybe even skipping one or two of them and not wrestling every single month), and then had Cena win the Royal Rumble and defeat Sting to win his record 16th title win? Now granted, Cena is already hated enough as it is (especially with smark-infested crowds like the ones at Wrestlemania), and him beating Sting in Sting's own hometown of Dallas certainly isn't gonna do him any favors, but that's never stopped them from doing something illogical before.
Cena vs Taker would have been perfect (especially if it were Taker's retirement match and he went out on top), but apparently a third match between Taker and Lesnar is a bigger priority.