Yes, I complained about this in EA several times in the last three years... it essentially fell on deaf ears. I got reply's like "it's a game, and too hard to code longer ranges". This 18 meter maximum applies to all spells as well, so its a total ranged character Nerf if you think about it. On hand crossbows though you are incorrect as the max range of hand crossbows is 15 meters not 18.
Fair enough, still more than in tabletop and 3 meters of difference is barely noticable. The fact that you can dual wield those things like some kind of akimbo guns is way worse than that. Thief is superior due to that.