When are we getting a crit reduction item?

Defensive mastery tree: Reinforced armor: Reduces damage taken from critical strikes by 10%

Blocks 10% of damage from basic attacks.

How would that even work? How would they balance that?

Well, there is the insane crit reduction mastery. It reduces the damage taken from autoattacks from IE+PD by 5.5% for a single mastery point.

I think just bringing back the On-Hit slow on Randuin's Omen would be a sufficient start for now.

The code is already in the game in the Reinforced Armor Mastery that reduces Critical Damage by 10%

While their at it why not overhaul penetration so we don't have people (Assassins and high damage fighters) buying Last Whisper to burst squishies and give tanks a run for their money as well. Flat penetration items should be for increasing damage versus squishy champions, Last Whisper and Void Staff for increasing damage to tanks.

#BringBackTanks2015

?????

or crit reduction runes could be cool

Oh, how the times change...