Neville
It would be an ultimate underdog story if Neville goes on to win the Money in the Bank. From what they so far, the fans love Neville and from the looks of it, WWE is pretty high on him as well.
Thanks to his high flying ability, Neville is almost sure to find a spot in the ladder match and if he does, he should go on and win it.
Neville getting over the likes of big main event names on a pay-per-view stage would sound perfect and it will also help him enter the title scene. The character direction and storyline aspect that Neville desperately needs will come along with the briefcase making it a 'best for business' move.
Bray Wyatt
Bray Wyatt was wasted in a feud with Ryback at Payback even though the match was of top quality. There was a clear lack of motives and story build up for the feud and it clearly hurt the entire effort that these two put in. The chances of WWE continuing the feud are low and this opens up the door for Bray to be involved in the Money in the bank match.
Despite being one of the most creative gimmicks of PG Era, Bray has been held back due to ridiculous booking decisions. An entry into the Championship scene could completely turn his career upside down. A cult creepy leader carrying around a briefcase might not turn out to be a pretty sight, but maybe WWE could sell him as the weirdest Money in the Bank winner.
Roman Reigns
Roman Reigns won the Royal Rumble, he headlined WrestleMania and we all know what's coming up next don't we? He is the best option that WWE has to win the Money in the Bank briefcase and the result will also add an extra layer to the character of Reigns.
The Samoan Superman is currently having a gimmick extremely similar to that of John Cena, which is also one of the reasons for fans hating him. By letting Reigns win the briefcase and letting him be an opportunist, WWE could show to the fans that Reigns is not a role model like Cena. From a larger picture, Reigns deserves this as well for all the efforts that he is putting in to improve his skill set.