VU was great but now we really need to talk about a GU for Karthus, Riot
His Q and W have been made obsolete now that everyone is getting far too much mobility and sustain built into their kits let's also not forget SO many items are getting MS stuck onto them. It's nearly impossible to land his Q(especially on an isolated target) and his W just gets canceled out by all the speed and mobility.
Then there's his E that has no purpose outside of dying since, being immobile, karthus can't really get near anybody anymore and in any sort of competitive game nobody will just walk into his E and stand on it to take damage. With the 
slow nerf it's even more difficult to get this thing to stick.
Then there's his ult why is there so many counters to this when it's got such a massively long CD even with CDR?
ult
Troll pole
ult
This is just to name a small few that can 100% negate the entire ult let's not mention all the CC that completely stops it if you aren't dead while using it.
Karthus at this point in the game has even less of a purpose than Aatrox and that's really saying something. He's in dire need of a gameplay update otherwise you might as well just delete him because he serves 0 purpose and there is 0 reason to EVER pick him over any other champ in the game.
