User blog comment:C4bal/Corki in the Tank Meta. How to./@comment-24036535-20150614163022/@comment-24036535-20150617153457

You've missed my point, the only champions who would be able to get to Corki after Valkyrie, are pretty much assassins, and we agreed that they don't really care about tank stats. Anyone who would kill Corki fast enough to prevent his Valkyrie, are assassins. Anybody who doesn't, won't be able to catch up to him AFTER he uses his Valkyrie. This means that overall, you're losing DPS because you dropped the following: Upfront armorpen, for lower overall armorpen, 30 AD outright, a good portion of the spellblade proc from Trinity 125% instead of 200%, 30% attack speed, 10% crit, and 8% MS.

That's a decent DPS drop for items that won't be utilized. I won't deny that those defensive items will help you after you get out of your GA, but GA has a five minute cooldown. You generally aren't going to be using GA more than once a game, MAYBE twice.

TL;DR, you only really need Valkyrie.