portugal: Different colors to go along with the different lengths would help differentiate them, too. For example, if the short lines were blue and the long ones red.
"short lines were blue and the long ones red", can you tell me what you mean by that? Lines seem to be the same length, it's just a matter of showing and arrow "->" for multiple squares (rook, bishop move) compared to just a "-" for one square (king, pawn, silver, gold). That already seems to be solved from the wiki page which has a circle instead of a line for single squared moves.
jadarite: from AbigailII: "One way to show the Eagle: arrows up-left, up-right, down. short lines up, right, left. longer lines down-left and down-right."