Did you just join this conversation? I literally said that he's got nothing but his ult.
Hell, take my 700 AP Karthus as an example. His ult hits for 970 before resists. Let's lower it to 600 after resists. With 5 targets, he's shitting 3k damage every two minutes and a half at rank three. If the match lasts 15 minutes after he hits rank 3 on his ult, that's 18k damage, and that's not even counting all the times he landed it before that.
Hell, look at his death stats. As a mid laner, there are only 4 champions who die more often than he does and yes, they're shit.
Again, except for his ult, shit damage, shit range, shit CC, shit survivability, shit mobility.