It would be nice to have the ability to freely move the image about inside the image window 
(as opposed to the current behavior of having the image restricted to the center of the image window if the image is smaller than the window, OR being unable to move beyond the edge of the image if the image is bigger than the window. )

I've seen this behavior in Corel Painter (and I think the recent versions of Photoshop), and I sorely miss it in the GIMP. It makes some things easier to accomplish (such as manually painting the edges of an image using a tablet). It also feels very natural. 

Thank you.