randuins omen x4

So i was thinking, since you can stack the - 10% crit damage. This might be the way to shut down adc's as a tank. You simply get 4x randuins + tabi + thornmail. With most of the adc items getting crit they will all end up having 60% or higher at least and if they wont their supps will probably get zekes and put them on 100% crit. This measn that with 4x randuins + tabi you get 50% damage reduction from passives alone. you can even get as much as 8% more from the new masteries.Turning you in to a perma ulting Alistar. On top of that you get like 370 bonus armor and since the new last whisper wont penetrate your base armor anymore you can get so much damage reduction that adc's will barely outdamage your base healthregen, i suggest taking the new perseverance mastery so you can outheal their dps when below 20% hp. Meanwhile everytime they attack you they will receive 15% damage dealt + 110 from your armor you accumulated.

Seems like a good plan to me for preseason 5 adc meta.