It would be nice if we could drag and drop items for their default action. E.g. drag an edible item unto the avatar to eat it, etc.
Also, when you want to sell something to a vendor (other than Uncle friendly), you first have to click "buy", then "sell" link. It would be easier to have a "sell" button directly when you click the vendor. Here too, I would expect that dragging the item to the seller would open the "sell" dialog.