Hang on.. So you get absolutely nothing for leveling Darius's W past lvl 1? Wot?

W - Crippling Strike Slow heavily increased. No longer slows Attack Speed. COST30/35/40/45/50 mana ⇒ 30 mana at all ranks COOLDOWN9/8/7/6/5 seconds ⇒ 8 seconds at all ranks DAMAGE120/140/160/180/200% total Attack Damage ⇒ 140% total Attack Damage at all ranks SLOW20/25/30/35/40% ⇒ 90% at all ranks SLOW DURATION2 seconds ⇒ 1 second REMOVEDATTACK SPEED SLOW20/25/30/35/40% ⇒ No longer slows attack speed REMOVEDCRIPPLED COOLDOWNNo longer reduces Crippling Strike's base cooldown per Hemorrhage stack on the target

EDIT Apparently it was just a typo (which they changed after I looked at it).