QoL changes to make Karthus a better champion

Karthus is in a weak state right now and now one wants to see him get buffs since his Ult deals a lot of damage late game ( it's becoming easier to avoid but that's another topic). He can be made stronger with little changes made to his existing kit that would make him a more fluid champion.

1. Remove the cast time on his Q and don't make him pause while casting it. His Q already has a delay, server lag adds another delay so does Karthus really need a cast time before his Q appears on the map? It's hard enough to land it but I'm willing to add a few more seconds to the delayed explosion if it was cast instantly. It would be better if he could keep moving and floating if he did it too.

2. W prevent dashes. It's a skill ment to limit mobility. It already has the slow fall off over time so if the 1st half only stopped dashes that would be fine. Something similar to Cass but this move only affects people who go through it.

3. Have E do same damage but more ticks. It is a shame that toggling E on and off is a legit strategy to get more damage from E. They even added a cooldown to E because it was abusive. Instead can it tick more often like Singed poison? Adding a longer cooldown to composite would be fine.

4. Global laugh on the ult. It's on one of the longest cooldowns in the game and isn't used ever time its up. Veigar has a laugh after ulting, Singed has one after flipping someone in his puddle. So would a Global laugh on a global ult be to much? Maybe only trigger if it killed someone, or during the ult, something to complement how epic a global ult really is