@Meddler: A question regarding a blink ability based off a BMB item

I'm making a new ADC Champion who has a blink skill that functions similarly to the Mirage Blade from Black Market Brawlers, but with a few tweaks. I'd like your opinion on it, if that's alright.

Here's a description of the skill thus far: >Passive: Your basic attacks apply a mark to your primary target for a few seconds. You can only mark one target at a time. (An indicator also appears to show whether you are "far or close" to your target in relation to the active effect.)

>Active: If you are further than X distance from your marked target, you blink a fixed distance toward it. If you are closer than X distance to your marked target, you blink a fixed distance away from it. In either case, you also gain Y% bonus movement speed for a brief time after blinking.

Would this be too hard for players to understand? Or could it work if properly laid out?