Hey Peter, just dropping this is a formal request in case it's easier to track.
I'd like to see real lines that you can drag around by the endpoints, to replace the "Arrow" widget that is movable only as a box.
Also, having them "anchor" to widgets would be nice.
Sean, this is one of high-priority items on my list. I added your vote to it.
Fantastic Peter, thanks!
Sean, the latest release improves arrows and you can draw and resize them using regular line handles: http://wireframesketcher.com/forum/topic/26477/feature_suggestion_arrow_direction
Let me know how this works for you.