So i have been maining warlock since the release for the dawning and honestly, Stormcaller isn't that overpowered. To start with, the grenades do not have amazing tracking or one shot damage but combined with arc web you can take out groups of guardians with ease. Thunderstrike, for me the only arguably overpowered thing about Thunderstrike may be feedback, but it does make it incredibly useful for PvE. The perk amplitude isn't overpowered since increasing the range is the entire point of the perk. Stormtrance, without ionic blink being a crutch there would be no real reason to complain about it at all. Yes it is strong, but you can not go invisible or get rid of it quickly so in PvE you have to commit to the fight. In PvP ive found superconductor to be more useful since you can chain lightning to the entire team if they are present. Stormcallers have no perks for evasion, health regeneration, or overshields. So in summary, the subclass is strong but it is very much balanced and relies on a Titan like playstyle to use to its full advantage.