I  just changed mine this weekend and mine had that left side wear as well after 8500 miles. Dealer says it is for sure alignment being off.
My buddy ran metzlers on his Texas Chop and went through 4 tires in 2 seasons because of left side wear. Dealer said it was perfectly aligned everytime, and it went in for check ups after the first two tires to make sure alignment was staying in.
I say....
The tire runs on the left of center because of the crown in most roads. AND when you crank on the throttle hard, you don't notice it , but you pull back on the right grip when cranking. That in turn would make the bike lean a bit under hard acceleration to run just left off center causing the tire to wear faster there.
Turn your tire around and run it the other way!!!! 
