That's not really an indicator of Subban being superior to Letang. Letang tied Subban in points while playing 7 less games. Letang averaged a point per game. So it's not unreasonable to think the 7 games he missed would have further padded his stats. His TOI would have remained roughly the same. His last three years Letang has averaged over 24 minutes per game. Subban has only averaged over 24 minutes per game once(11-12.) Subban also averages more PIM than Letang.
Nynja control your boy.