With this in mind, are there any planned changes to Karthus E? I think it's the only toggle ability left in the game aside from Jinx's Q (which is fine).
I think Karthus is quite low on the list of priorities for work but I think his E is fairly uncompelling. At least it automatically turns on while dead, now. It didn't used to. I also don't know if anyone even agrees with my sentiment.
Jinx feels solid. I think she's the one toggle that feels well-done since choosing on/off is actually meaningful and is reinforced with every attack.