Kai sa kit is too weak/lacking for a 500 range adc
She not a good laner, she doesnt have real mobility or a dash, she doesnt have a spellshield, she doesnt even have cc and most of her damage is blocked by minions...
Like compare her kit with xayah or vayne... Or any other adc really and you'll see how bad it is.
Like why in the world does this champ has 500 range? Were they trying to make the worst adc imaginable? Because if they were, they did it.
