There are some challenges with a feature instance setting for the dropped file upload location.

The service url that handles the file upload is not aware of the feature or page that is posting to it. It only knows about the current user file system permissions and where the root folder of that is ie media or a user specific folder for some users. 

So if we made a setting at the feature instance and if we managed to pass that setting as a parameter with the upload there could be a case where the setting location is not allowed by the current user who does have edit permission but has less privileged upload permissions, in which case we would have to just log the error and maybe fallback to the user allowed location.

If the user wants to upload to a specific location they can still select the location and use drag and drop on the file dialog page. So we're talking about a few clicks difference to get complete control vs less control but easier.

Not saying it couldn't be done, just saying that there would be a few challenges.

I will probably get to this at some point, if someone wants to sponsor the development effort then it could be made a priority.