Do you think that Veigar's E having 0.4s delay instead of 0.5 would be OP?

Honestly. I think it's like everything he needs. He feels a slightly bit not reactive enough. Is it such a crime to have a non "clean number" and just put it to a slightly lower value like 0.4 s so it becomes reactive but still rather dodgeable, keeping its counterplay. The buffs to Q and W are already really good, I think he'd just need that and he'd be perfect. And I want to make an emphasis on the fact that a really small buff does not make a viable champion overpowered, he stays in the viable, but not OP margin.