I honestly feel like karthus is high skill/low reward sort of champion.

I'm not saying hes bad by any means necessary, In fact I love the champ and play him quite frequently. But his Q is a skill shot that is super hard to hit and offers low reward for doing so. you get a nice 500 damage burst or what not (usually less) for hitting the Q on an isolated target. Yes the Q is quite spammable but honestly I find it the most difficult skillshot in the game to hit. It requires a lot of practice to even get close to good at karthus and I feel like even when you are good with him there are just easier champions with easier skills to hit that will do so much more than you.

Imaqtpie sums it up nicely. https://youtu.be/6LxRXgDfHdc?t=3m25s

So what should we do for karthus?