The short answer is you die because it's a super. If it was so weak that you could take it out with a few primary bodyshots as if it didn't make any difference at all or just slowly amble away, well it just wouldn't be super. Stormcallers have no health or shield regen/overshield, the range of the actual attack is pretty low (I've been shut down by 2 people team firing not very far away PLENTY of times, and quite a few times by 1 person quick on the draw with primary alone), the time - if you don't sit on your melee or grenade for transcendence - is short and shorter still if using ionic blink, and all the grenades for the class are largely awful. It really, really doesn't need a nerf!