I think the issue there, which has been also discussed in the past both in forum and privately with some devs, is that normally leatherworking makes "protective" things (armours, boots) and a type of container, while it'd require having also some "attack" thing coded. Also whips could be made with leatherworking if you think of it. It is somehow the same issue with woodworking and clubs and quarterstaff (woodworking makes shields or ranged weapons only). Unrelated to this, though, maybe protective belts and/or gloves may be added more easily.