I still don't see much interest in this yet...
Maybe altcoin values aren't going down a whole lot lately or something? It seems quite possible that a lot of the interest in shorting is not really an intent to drive down the value but just to profit from the already lowering value. So maybe it is more a feature for opportunists than a feature for those who actually want to try to drive down the value of something.
Part of the interest in it on my server is from debtors. They heard that shorting can somehow sometimes drive down the price of something, which got them interested in trying to drive down the price of whatever their debts are denominated in so as to make the debts easier to pay off.
-MarkM-