Quick idea for a reworked Nasus Wither.
Withering Sandstorm: Nasus creates gusts of crippling wind in direction of a champion. The zone is cone shaped, centered on Nasus and always pointing toward designated champion and persists for 5 seconds. The cone is 700 range long, but has a 300 range deadzone without winds. Those caught in the wind are slowed until they leave the zone. The slow is strongest at the outer edge and weaker toward the center.