can we an official riot context on karthus

what do you think about him?why he hasn't a global quote when even illaoi and kalista have it while they have nothing global in their kit?why you nerfed his only defense against assassins when they already hard counter him in the same time you buffed zed?i mean please give your opinion on karthus i can't stand it i made a thread about him which got 600 likes in 1 day and 0 riot answer