New tank items

Based on the recent resurgence of "buff tank" mentality -- specifically the fraction that wants Void Staff and Last Whisper nerfed -- I feel a few, new tank items are warranted (besides Zz'rot Gate).

For example: an item designed to counter percent penetration.

Damage is a counter to health, mitigation is a counter to damage, and penetration is a counter to mitigation. Rather than suggesting yet another, non-interactive stat in this chain; why not add in a temporary, active counter to penetration. A short up-time means that tanks can still be killed, while the tank would still have a window where they get their end-game fantasy -- shrugging off tons of damage.

It would take a 53.84% mitigation increase to negate Last Whisper and Void Staff completely.

My solution would be to bring Guardian's Horn to Summoner's Rift as well as introduce a piecewise upgrade path to counter the %pen items.

Something to this effect:

War Drum (2,000g) Guardian's Horn + Chain Vest + 225g +200 Health +100% Base Health Regeneration +40 Armor

Unique passive: Enemy spellcasts reduce the cooldown of War Cry by 1 second. Unique Active: War Cry: Increases movement speed by 20% and increases bonus armor by 45% for three seconds (45 second cooldown).

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War Drum (2,300g) Guardian's Horn + Giant's Belt + 275g +600 HP +100% Base Health Regeneration

Unique passive: Enemy spellcasts reduce the cooldown of War Cry by 1 second. Unique Active: War Cry: Increases movement speed by 20% and increases maximum health by 22.5% for three seconds (45 second cooldown).

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War Drum (2,125g) Guardian's Horn + Negatron Cloak + 250g +200 Health +100% Base Health Regeneration +45 Magic Resistance

Unique passive: Enemy spellcasts reduce the cooldown of War Cry by 1 second. Unique Active: War Cry: Increases movement speed by 20% and increases bonus magic resistance by 45% for three seconds (45 second cooldown).

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In this form; the items are each 85% gold efficient without the active and over 100% effective during the active duration (increasing as more items are added). As you can see, it only mitigates the penetration of one type of damage, so a tank isn't negating two pen items, simultaneously (and the net effect to would still be -9% penetration with a Last Whisper or Void Staff.)

Giving the tank the choice of when to mitigate, as well as the choice of what they want to specifically mitigate, gives more strategic diversity than an end-all-beat-all item that simply negates Last Whisper and Void Staff by sitting in the inventory.

On a level 18 Garen with the following build (no runes/masteries/ability effects):

War Drum (Armor version), Randuin's Omen, Spirit Visage, Mercury's Treads, Thornmail, and Banshee's Veil

His stats are HP: 3,894 Ar: 286 (258 bonus) Mr: 190

Which means that the armor version of the War Drum item is 214% gold efficient during the active duration (spiking armor up to 402 for 3 seconds).

The one thing that I'm concerned about is its use on bruisers. Giving every champion a fairly potent defensive steroid like this can easily make it another Guardian Angel.