All the problems with LoL that Riot pretends aren't fixable
Actually are.
HotS has done/is doing them.
Balanced stealth. More or less solved AFK issues (could still be better but it's in a great direction.) Less toxicity because of the way their entire KDA/power-shifting system works.
So, what's wrong with Riot's balance team? Seriously. Another game not unlike theirs has shown them how these "unbalanceable" systems can be balanced, yet they still pretend it's not conceivable. I envision children plugging their fingers in their ears, and shouting to themselves.