How does a 6th man win multiple player of the weeks? When he's the team's #1 scoring option. 
I really enjoy watching IT. Glad he's on the team. I agree with Jackie Mac, the team has become much more interesting since he was acquired.
That said, I think my vote for 6MotY would go to Nikola Mirotic.
IT seems like the clear choice over Mirotic. I realize that he had a couple of rough patches this season, but the 10PPG on 40%FG in 20MPG doesn't seem like quite enough for the award - even though he has had quite an impact lately.
I choose Mirotic because I think he's the best bench guy in the league who plays the sixth man role. It's not all about scoring points.
IT is the most productive scorer coming off the bench in the league, but he's also the team's number one scoring option. I just don't really think of him as a true sixth man.
I forgot where the "sixth man role" is defined and what a "true sixth man" is. But more importantly, let's penalize a player for being good, makes sense.
It's totally subjective, just like MVP. Your definition is as good as mine. I just don't view IT as a sixth man.
If anything, it's acknowledging that IT is too good to be viewed as a sixth man. He's the best player on our team. The sixth man award, in my mind, is supposed to be a recognition of the guy who does the most for his team even though he's not one of the main guys in the starting lineup.
I love IT. I wish it weren't so difficult to use him in NBA 2K, cause I'd use him all the time.
The problem is that your "vision" of what a sixth man is completely ignores the tradition of what is actually considered a 6th man and what his role is, going back to the Auerbach coaching days with the ultimate 6th man in John Havlicek and other players he had in that role prior to that.
Your vision of 6th man is a bench player who pretty much is like an ultimate role-player, when in fact the 6th man role in its purest form is for a player who is pretty much a starter level talent, among the best in the team, but for one reason or another you have him coming off the bench.
So that IT is that good shouldn't be held against him particularly with his offensive output, in fact that's the epitome of what a 6th man is, much like The Microwave.
So in all, you're trying to pigeonhole what a 6th man is while completely ignoring the role why it was first introduced in the game.