How much the arrow keys move a selected object around in any direction **w.r.t. the zoom level**
I think the primary goal of letting us control the object with the arrow keys is so we can be accurate with it's placement on the artboard. But this becomes completely useless if the zoom level is very high, in which the arrow keys moves the object a big distance. This forces us to use the mouse to get the accurate position for the object.
For example if we've zoomed in, then let the arrow keys move the object a smaller distance than usual, so that we can be more accurate with an object's placement with the arrow keys. I think anyone would find this ability useful.