Thanks so much for your input everyone!

As far as the IE, I didn't use it on purpose. The point of this build is to make Yi invulnerable to thornmail, his number one enemy, by increasing is lifesteal to 30 percent or greater. By doing so, the 30 percent damage return done by thornmail is eliminated by the 30-40 percent lifesteal, which even leaves 10 percent lifesteal with 420 AD and 60% critchance, averaging ~1200 raw physical damage per second with ult, and about 120 health return per second.

These numbers are aproximated, but they show that the IE, while doing more damage, is not a good way to play against any team with half a brain. After Yi takes his first few kills, they'll wise up and buy thornmail, and Yi will become dead a lot. Built this way, and played as he normally would be, he'll be dealing plenty of damage while not dying at the same time. This means killing more than one enemy in a team fight, and diving that tower after killing the player protecting it. This Yi is a steady burn as opposed to a bright flash.

This guide REALLY needs an IE, with two Phantom Dancers, your crit and attack speed would allow you to demolish the enemy. Remove one of the Bloodthristers and replace it with an IE, and the guide would be solid.

No IE? That would really spike damage.

not a bad guide. Easy to read. You do have a mistake in the summoner spells section, the ignite. Also you dont talk about all your items, you have 2 bloodthirsters and some other item in the items list. Also for the runes its boring to read and hard to understand. You should include some visuals. Your guide will be better if you add some color, organisation and columns.

Pretty basic and standard, I like that. However why do you not get an Infinity Edge? I was slightly disappointed upon seeing that.