[Say, it isn't that bad!]

It's been years since I trained in karate, and the training was only some months - But I can still punch about as proficiently with my left hand as my right. If there is a skill penalty, I can't detect it in casual testing. All of my punches, left or right, seem to go pretty much where I aim them.

The -2 ST penalty, though, seems about right.

Using a plastic Halloween sword hanging around, my left hand does seem not as nimble as my right.

Overall, it does seem reasonable - Although I'm very far from an expert.