I have the same wheels, I was informed by the dealer when I picked the bike up new that the wheels where alloy and not lacquered (they are painted between the spokes) and would take a bit of looking after and not to be bringing the bike back back and complaining after riding it through the winter
I have just over the same miles as you, although not out in salty roads.
I gave the wheels a polish with solvo for the first time last month, took about 1 hour, and it did make a remarkable difference to them, they where slightly tarnished but I had no pitting as you seem to describe.
I recon they do take a bit of looking after but are ok so far, they would look good powder coated black, especialy on a black bike.
