I agree... however I do think "Well, you broke an arm. You lose 1d4 strength" is a quick and simple penalty, I would also certainly follow up with things like "No, you don't swing your sword. You arm is broken, remember?" or whatever else.
I mean, by all means, embellish on the injury. Leaving it a loss of a few stat points and carrying on would be an injustice (!!).
Of course, if you wanted to make up a more complex chart with all sorts of fun things on it, that would be sweet too. It's always been, however, one of my biggest issues with the D&D system however.
Joe Blow gets shot by a cannon and takes 39 damage out of his 40 health. He fights on as if nothing has happened because there is no penalty or issue in the loss of HP (by the numbers). I've seen all sorts of pain systems and maim systems and a balance is tough between making things -too- deadly vs too much like a game of Final Fantasy. I think the ST making up things works well, but a touch of guidance never hurt, right?
Just my two cents anyways.