kleptomancy Idea

what if kleptomancy is a trade rune for example if you jax vs makoai you should out damage him in the trade that you initiate( right ), so the idea for the rune to make you get "something" when you do more damage then him in the a trade but he must have did damage to you also so that range don't abuse it and the ezreal and gp can't use because he have to hit you back example again draven hit varus with basic attack so do varus basic attack draven and give him the klepto proc "because draven basic attack do more damage than varus basic" or don't or take the trade to all in i feel it would be good for lane bullys and maybe make the "something" better if you use mana in the trade

thx for reading

disclaimer: English is not my city