Some karthus changes that would be nice if put in the game.

A while ago i started playing karthus and i wanted to buy a skin for him while grim reaper karthus splash looks sick but he looks nothing like the splash in game and i think thats falce advertising. Another thing id buy pentakill karthus because of what he says when he ult but why not make it so that everyone on the map hears what karthus says when he ults i think it would be a nice change. The problem i have with grim reaper karthus is that he just looks like an old man in game. If riot could just make the skin look in game as it does in the splash it would be such a cool skin.