Can Karthus get buffed
He got a pointless nerf when he wasn't even good before mage rework. Mage rework did nothing to help him. I think it may have even gotten worse because most of the items are really pointless for what his kit needs.
Maybe give him another passive on his E. For every enemy champion standing it generates +1/+2/+3/+4 AP per second until it is turned off. With the upgrades being with his ult tiers. And maybe give him like +50 base hp. Barely having 2k hp at lvl 14 with a rylias and a haunting guise is ridiculous.