That's the same reason I always hear and the only thing I ask of that is; did no one try to kill the stormcaller? You truly would have had to not have been trying if a stormcaller doubled wiped you. And it's no surprise that a stormcaller can wipe an entire team in one go. People panic and group up which gives a stormcaller the advantage. If a stormcaller was able to double wipe a team, you're a bad team. Stormcallers are easy to shut down.