AL MVP: Josh Donaldson
Donaldson leads the American League in context-based offensive statistics like RE24 and WPA, and exceeded his primary opponent, Mike Trout, in defensive value according to UZR and DRS. His context-free aggregate stats (e.g. wRC+, WAR) are comparable to Trout and the other league leaders and he exceeded the values of those other players when considering context. Donaldson will win the award and some will brand that as a function of his team making the playoffs, but I really do believe that he was more valuable to the Blue Jays than Trout was to the Angels in 2015.
NL MVP: Bryce Harper
What is there to say? Harper had a season for the ages, no matter whether situational context is considered. Anthony Rizzo led the National League in WPA, piling up over a win more than Harper, but to me that's not enough to exceed the total value provided by Harper's great season. WPA is a good stat that tells a story but it can devalue important run-scoring activity that occurs early in games. Harper's production with runners on base (wRC+ of 195) and in scoring position (163) were great, fueling that outstanding 79.31 RE24 runs total.
AL Cy Young: Chris Sale
I explained my thoughts on this race here: http://www.breakingblue.ca/2015/09/29/chris-sale-and-a-different-way-to-look-at-the-al-cy-young-race/ . I believe that Chris Sale is the league's best pitcher.
NL Cy Young: Clayton Kershaw
By similar reasoning, I believe that Kershaw is clearly the National League's best pitcher. He is having an absolutely monstrous season. Arrieta and Greinke really only have ERA arguments over Kershaw, and I don't put a lot of stock in those arguments when it comes to determining the best pitcher.
AL Manager of the Year: Kevin Cash
I was really impressed by Cash this season, including how he frequently pulled pitchers after the second time through the order. He seems to get along with the players and have a good handle on soft skills too.
NL Manager of the Year: Bruce Bochy
It's crazy that Bochy hasn't won this award with the Giants yet! He's proven year after year that he's a great manager.
AL Rookie of the Year: Francisco Lindor
Lindor piled up a ton of value and was the most outstanding rookie in the AL this season.
NL Rookie of the Year: Kris Bryant
There's not much debate here. Bryant is even a fringe candidate for MVP.
World Series: Dodgers over Blue Jays