Create an AP item that provides something similar to Ornn's tenacity reduction

Playing most casters who are heavily reliant on a CC ability at high MMR is a nightmare, because there's so much tenacity in the game, and it's already very hard to land skill shots with all of the movement speed floating around, especially towards the late game.

It's basically guaranteed that your opponent will take Legend: Tenacity and build Mercury's Treads against one of these champions, which gives a 50% reduction in CC duration.

Lux, for example, is completely destroyed by opponents having this much tenacity. Her E has a 0.85 travel time at max range, plus delay on the explosion, and her ultimate has a 1 second cast time, also delayed by the animation lock on her E. If her snare only lasts 1 second, it's nearly impossible to combo any champion with a dash in its kit, because they get out before it lands.

It would be nice to see an item added to counter this. Movement speed already provides enough of a counter to casters; there's no need to also have this much easily available tenacity.