Karthus is problematic.
I don't know what's worse. His overall AP DMG that he dishes out. His absurd Ult and the DMG that puts out or his death ability and the DMG that puts out. Now, I know many of you will tell me to build on my Magic Resist, and that's fine and all; I accept that criticism. However, even when I go that route it still seems to do no good for me.
All around, I say Karthus is a HUGE problem in the AP DMG department and he needs, no, DESERVES a NerfHammer. Even if it's a 10-15% cut on his overall AP DMG potential or drop his armor and/or HP by the same percentage, I'd be satisfied. It's ludicrous having more than 30% HP and than getting destroyed from half the map away because a Karthus decides to Ult. It's beyond absurd to me and I'm sure many others and I believe Riot needs to drop the NerfHammer on Karthus.