A Thought-Bunny For an ADC Item for Immobile ADC's

The idea came up to me when i was thinking how a lot of the full-build critical chance items had 30% critical strike chance, and how there could be more 20% and 10% critical strike chance items, and the idea for this came to me: an ADC item catering to immobile marksmen.

The item would build out of Zeal and a B.F. Sword, it'd have a combine cost between 600 to 900 gold, so not exactly a cheap item that you can rush.

It would grant moderate damage and attack speed as well as 20% critical strike chance.

It would have a Unique Passive called Deadeye: After {3-5} seconds of not moving, basic attacks and single-target spells would stack 'Perfect Aim,' which increase AD by 5% and critical strike bonus damage by 5% per stack, up to a maximum of 10 stacks. Movement after having built up stacks consumes {two stacks per 100 units} of movement.

It's not the greatest idea, but I felt ADC's like Ashe, Varus, Caitlyn, and Kog'Maw could use an item that would take advantage of their comparatively immobile nature versus the Vaynes and Lucians and Ezreals that are often seen.