After thinking about it more... I'm totally on board with Roman winning the title. Hell, if the story's right it can be exactly what both characters need to get on the right track!!
There's plenty of out of kayfabe reasons to be okay with it, but lets just tackle this in storyline.
Lets start with Seth. Much of the reason his title reign has been such a fail has really been because we don't have a reason to hate him. Almost any conversation about Seth comes down to "writing" and "booking" and "formatting" and all this crap that gets the company heat and not Seth... So why should we hate Seth? Because he ended the Shield, because he attacked the group we loved so much and traded away their brotherhood for a championship hand-delivered by Kane (in an angle only Jon Stewart paid attention to).
Largely the same issue on Roman's side, as Stopspot put perfectly during the Rumble, the issue was that Bryan had all this buildup and all these reasons to get behind the guy while Roman really didn't have any. He was simply "the next top guy, dammit!" after we saw Bryan get killed off time and time and time again... Look at the awkward way his character went. He was attacked by Seth, then while Seth and Dean were in the ladder match, Roman started to climb towards the title picture and get awkwardly handed a title shot at Battleground... then he had that pointless feud with Orton, then had the hernia while Dean was wanting to rip Seth's ears off and shove them down his throat and beating the shit out of him with everything he could find inside the cell before getting completely distracted by a ghost lantern and the revenge for the Shield was dropped... and now's our chance at a happy ending.
This is Roman's first real shot at Seth, right? I mean, maybe they had a forgotten Raw match or two, but now you're main eventing a PPV for all the marbles. This is the biggie. After all these teases and reunions lately, now's the chance to pay off the Shield breakup angle and let Reigns beat that ass with Ambrose laughing maniacally on the outside.
Fist bump. Believe that.