Lich Bane Nerf - How to buff AP Ezreal to compensate

The Buff of 0.2 -> 0.4 AP Ratio is not enough for AP Ezreal because his Q deals PHYSICAL DAMAGE. I propose a change which would introduce a new & interesting mechanic - if it is possible. If Ezreal's AP is higher than his AD his Q deals MAGIC DAMAGE, if not it still deals PHYSICAL DAMAGE. This would buff AP Ezreal - making him maybe even viable in another Meta, yet AD Ezreal doesn't receive a nerf but too a minor buff because the AP of Triforce now scales with 0.4 instead of 0.2, meaning 6 more damage per Q.

TL;DR: Buff Q from 0.2->0.4 AP ratio (as on PBE); If AP>AD Q deals Magic Damage, if AP=/<AD Q deals Physical Damage