It would be nice if you could choose objects listed on maps (highways, towns, state borders, whatever) and having the option to right-click on them and "avoid area" them, rather than drawing a shape to avoid.
It would also be nice if, after you've designated an area to avoid which disrupts a previous route, the program automatically planned a replacement route. It's not like I'm going to say "avoid that spot; but don't bother showing me where to go now. I don't need to know." Maybe put a checkbox for "Automatically update routes when routes have changed" somewhere? ...Just in case someone out there doesn't want that feature?