This year's All-Star rosters are surprisingly good. In most years, this exercise is hard to finish because there are so many dubious selections and glaring omissions, but this year, there are only a few of each, and most of the problems either come from an obsession with relievers or from glaring shortages at specific positions.
My philosophy on the All-Star Game is simple: The point of the game is to showcase the game's stars, not the best performers for the first 70-80 games of the current season. It's a single night to market the sport and the league around the world in an event that casual fans will watch. They expect to see some names they recognize, and most of the game's most talented players. We shouldn't give them Jack Armstrong just because he got a bunch of wins in the first half. We should give them the best the majors have to offer, because that's how we'll convince them to be more than just casual fans in the future.
American League
The big omission here is Evan Longoria, who is one of the best all-around players in the league when healthy, which he is this year. The roster has just two third basemen, Miguel Cabrera and Manny Machado, but Longoria's a better choice than Machado, who could also sub in at shortstop, which is the AL's weakest position right now, allowing us to get all three players in the game (the ideal solution).