A blur tool that allows you to anchor one end of a path, then move the path that smudges the area you move over.
I routinely need to blur things that need to appear to rotate - think propellers or fan blades. I find it difficult to maintain the correct radius specifically with objects that may be painted as different colors leave their own colored trails in the smudge. To have a Smudge tool that you can anchor on one end, and then move or rotate the far end that keeps the proper radius of everything between the points. Perhaps you could even add points along the path (like illustrator) which you could also move, leaving other points in place, and smudge those moving points.
