It would be great to have the ability to do a cut-out in a line or arrow --- particulately the curvy double-arrow line. This would be useful when needing to cross another line, and avoid making a messy spaghetti bowl of lines and arrows.
I frequently do comparisons of two different tables of data, and need to be able to point to the same items in each set with different colored arrows. Frequently the data are not arranged consistently between the two tables, so my lines will cross. I use the curvy double-arrow line to avoid some crossovers, but it's not always enough. It would be great to be able to make a line, but have a break in it so that it drops off before crossing another line, then picks up again afterward. The user should be able to set the break points as the last couple of clicks in placing the line/arrow.