Do not mistake AP Ezreal's burst, because of Runeglaive.
Ap Ezreal ALWAYS did the burst he does, he's always been able to one shot someone, his ult always was able to take 90% of your health, its only good now because runeglaive gives him that little boost he needs early game to get to the monster he was late game.
I had a freaking Master Tier player who thought ezreal didn't do that much damage before and argued about it because just because he's master and im gold.... Lol