Storm callers are fine the way they are, they can bee killed in super by a sniper shot to the head or a shotgun/melee. In order to have a long super you have to spec for it and not use your grenade or melee for the perk to work. They actually have to plan the use for their super. I main all three classes and have no issue with storm callers. They don't get health back on each kill and have to be somewhat close to hit you with it. I run radiant skin with HoPF and firebolts for 6v6 and people have a way harder time killing me than ST.