Why to make AP Ezreal actually pretty good
Make his Q deal magic damage, at least for the ap ratio part.
Main reason why Runeglaive was so good on him, cause it made his Q deal entirely magic damage. The aoe to it was a bonus to it being good for him.
It so frustrating to see how your damage is invalidated as AP Ezreal on Q due to the enemy team just leveling up, and you are in no way gonna get armor pen.