One thing you'd have to change about the item is either give it on-hit damage or make it not built out of
.
It is a nice concept, but i dont think you've properly thought through the consequences of having such a generalistic anti-AD item. Not only does it grant armor and attack speed in the same item, it also grants straight up uncounterable damage reduction.
The item looks appealing to me. Until i think about something a lot of people are incapable of visualizing what this would be to play against. Not just assassins - bruisers and even tanks (heck, bruisers and tanks will want this MORE than assassins) will pick up this item, and couple it with
.
I figure these champions would absolutely love this item:

I hate to say this, as this is one of the better item concepts i've seen on here. I'd want to use this item myself - and i main top lane tanks. That i would want to use this means everybody else would, too.
I really like the idea of this item. I hope Riot does look into it.
Not hating but wouldn't it be really strong on "on-hit adcs"? They only build Runaan for the extra bolts and they don't carea about crit