New Item Passive Idea

With tanks being so fast these days, I recommend a new item passive:

when attacking, Grants 1% move speed for each <insert HP amount> health that the champion being attacked has larger than your max HP for <insert time (I recommend 1)> second(s).

This would be a strategic purchase that AD Carry champions could buy in order to kite/chase better.

If the typical HP of a Tank is 4k, and typical ADC HP is around 2k, the difference is 2k. As an AD Carry player, I think a respectable amount of movement speed would be 8-10%; this would help kite, but you would still be vulnerable to champions that get a LOT of mov speed: Volibear, Mundo, Skarner etc. Meaning that the HP amount would probably be around 200-250. ]

A lower amount for this might be too op, but I think that if this was put into LDR, it would fit perfectly with the idea of having usefulness to kill tanks, but little other strategic value.

Thanks for reading!