What do you guys think? Give me some options and I'll make a poll.
To me it's by far the Unbalanced Gear Requirements - namely Carbantis and the Stun Twins.
Nothing is more soul-destroying, more phone-smashing, that finally unlocking a character, looking up the requirements, and seeing 500 Carbantis are needed. And the worst thing is this seems to be closer to the rule than the exception.
For the record: I love the game, quit another mobile game I played for over 2 years after trying GoH. I just want it to be as fun as it can be, and every character needing hundreds of the same item, while having a stockpile of thousands of the "same rarity" that never get used, is not fun at all.