5 seconds stun - i mean slow — Nasus

So, from the second he was released, Nasus's W remained unchanged. And it's actually disturbing as hell. W: Nasus ages the target enemy champion for 5 seconds, SLOWING them by 35% and CRIPPLE them by half that amount, both INCREASING over the duration. So, you basically have built in frozen heart&iceborn gaunlet in one power except its ridiculously stronger than both. That thing needs to be nerfed. I understand that he's based on stacking Q's and that he's a tank that needs a gap closer, but a five seconds slow / cripple ( almost a stun in the late game ) is just too much don't you think?