I need to know Riot, what are your thoughts on Karthus?

I mean most threads I come across are about how him and maybe a couple of other mages feel too weak to play right now, and that's sad since I'm a diehard Karthus main (and tbh I've always had the hardest time trying to get good with anyone else imo).

However apparently, Riot seems to think karthus is a little OP at the moment and nerfed his W. Granted, when Karthus gets a Rylai's he's slow city, with it being a first core item on him (yes I still get tear for AS later) but I feel that Karthus is actually in a pretty lousy spot at the moment with just about every new champ and their mother getting an anti-Karthus ult ability as well as a supposed new AD Assassin item in the works which certainly won't help Karthus's case in the slightest.

Look I'm just asking, when Riot does this Mage update thing, (I'll be patient and wait for it lol) I wanna know if Karthus will be able to keep up with all these changes.