Well if you nerf commandos nerf stormies give them cloak on cooldown.
Stormies av a downside for using there cloak ( moves really slow and can get ran over while in cloak). Also once they attack or get spotted they get rushed by units and av to retreat off the map. Unlike commandos that don't have no downside from using smoke. ( Go invisible for 6 seconds and take no damage from fire, move at full speed, can use grenades and shoot while invisible.