The reason you take Mike Trout over Chris sale is impact. Trout has the ability to impact 150 game per year, Sale has a chance to impact 35.
The difference between Trout and say, Miguel Cabrera, Miguel can change the game with 1 swing of the bat.
Trout can change the game with 1 swing, but also with his speed and his defense.
If you were offered Sale or Trout, pick 1, and you picked Sale, you be laughed at.