I don't think that he will be voted as sixth man of the year for the same reasons why David Lee didn't make the all-star team.First reason is that the NBA makes a habbit out of acknowledging the best players of their elite teams and cares very little about rewarding good players that play for below average teams.For example if your name isn't Manu Ginobli, Rip Hamilton, or Lamar Odom the odds of you winning such an award are against you.It's similar to this forum, if your name isn't DatPrince, metrocard, Red, or turneraddict then your posts will get little to no responses.
Second reason is the D'Antoni system excuse.Anyone that has success under Mike D'antoni will always be viewed as a mediocre player that happened to be under the right coaching system.People like to credit the system more than they credit the players that performed well.And that a player such as Nate Robinson would be an underachiever with any other coach.