I'm not such a hardcore league player. Sure, i do play a lot but i'm not into that much stats and stuff like the most of the players here.
Why can't Kayn be a no-cost for casting abillities champion? He has so many issues so making him this type would help him a bit. I lose all my mana in a single jungle clear in late game without blue buff. I always need blue buff to stay 1-2 mins in the map before reseting for mana. Even if I'm carrying the game, after killing 2 people i would just run out of mana and reset and ruin the push of my own team. Buff his mana stats, growth or regen, make his mana costs lower or just make him no-cost for casting abillities champion.