The State of Boots

Currently, boots are in an interesting spot. While very important for all chanpions to buy, so why are the options very limited?

Armor boots - very common, useful in most situations

MR + Tenacity boots - very common, especially against heavy AP comps or on champs that get kited.

Boots of Mobility - common on most supports

Sorcerer Shoes - very common on any mage or AP assassin

Boots of Swiftness - uncommon, only juggernauts have a need to buy them in order to not be kited

Beserkers Greaves - common on adc and other aa reluant champions.

No armor pen. boots? Don't nerf the other armor pen items, or any ad/tank will be unkillable. With the removal of armor pen from Enchantment: warrior, the only items that have armor pen are Yomuu's , Black Cleaver, and Last Whisper ( the two upgrades are not very different.
Magic Pen items haven't changed that much. Liandrys still gives solid M.Pen. Void Staff does the same. The AP champs can buy boots that do this too.

Moral off the story: add Armor pen boots to balance the tanks who are taking advantage of OP armor.