Shadow Assassin Kayn rework

What is your opinion on Shadow Assassin Kayns passive being changed so that instead of doing a percentage of your ad as magic damage, you gain bonus ad scaling with your movement speed. This would encourage more setup when assassinating squishy targets. Kayn instead of doing conssistent burst damage through any setup (through lethality and high ad and additional magic damage) would have to use his E and items to setup a assassination. It seems to fit his persona more in the way that he quickly emerges from a wall kills his target then leaves.