@Riot: Crit Counter Item

Since ADCs and assassins are heavily established in the meta and overwhelmingly rely on critical hits to deal out late game damage, can tanks and fighters have an item to diminish the impact of critical hits? We have as a counter to magic damage that has situational power (since the shield has a decently long CD), but the corresponding physical damage item doesn't really offer as much utility.

Maybe an item with armor + mana/health, and a passive that reduces the extra damage from crits to 50% of the opponents AD?