An idea to make Veigars ult a little fair

What if instead of just having access to an ability with insane damage the moment he hits level 6, His ult had scaling changes according to level like Jhin's or Rengar's Q. Instead of being one shot the moment he hits level 6, he had to work to get you lower on health and then ult as an execute, not just tossing it out when you hit 50% hp and still killing you. He would still have his insane late game strength but would get toned down earlier so he can't just snowball and be unstoppable before 20 minutes.