#1. Big E was the best and most realistic option to win the briefcase

Big E was a part of one of the most stacked ladder matches in Money in the Bank history. This year's line-up from RAW and SmackDown comprised of fresher superstars and other exciting names.
Each superstar had their role, apart from just the winner Big E. For one, Drew McIntyre came close to glory, only for Jinder Mahal, Veer, and Shanky to cost him as expected. This sets up their SummerSlam program.
Cody Rhodes' uncle is a WWE Hall of Famer. More details HERE.
Kevin Owens' role was evidently to take the biggest bumps - something he does more often than we realize. Ricochet and John Morrison had the "high-flyer" role - with both men impressing in a big way.
Riddle was great as well and so was Shinsuke Nakamura. Seth Rollins was meant to be the "thorn" in the match, with many fans not wanting to see him capture the briefcase for the second time.
Perhaps that's why Big E landed the big ending on Rollins before claiming the victory. He was the most realistic option to win the match and although it was stacked, Riddle, Ricochet, etc. weren't as ready as Big E.