Please nerf Xin's Sustain

You added an AD ratio to his "every 3rd attack heal" effect but right now on very little AD, hes out sustaining focused burst on him. Of course isn't helping matters but that + the auto crit means he almost always wins fights unless you rush executioners. Mages as a result are screwed because the heal reduction for them doesn't kick until 40% hp. The heal right now is op! Please nerf...