Outstanding build, you seem to really understand how Yi works. +1

Demo you are over looking the second effect of Ghostblade. It also gives Yi 50% AS. If it has diminishing returns so be it, but that extra AS means that his passive will come faster. Which means he will have more burst while under the effects of both Highlander and Ghostblade.

To answer you about Yoyo late game. No one kills turrets faster than Yi. If you need to make a push or Backdoor, Yi is the one to do it. Popping Ghostblade+Wuju Style= Turret Buster

IDK about you, but using ghostblade to kill turrets is better than using Highlander. Its better to have Ghostblade, and use it than using Highlander. If one to use Highlander to chase than there is an issue.

Highlander=Ganks and kills

Ghostblade=Turret Busting

The thing that makes Ghostblade better is if it is combinded with things like Starks and Black Cleaver. If you add to the ArP, it will be more effective late game. Ghostblade is an early game item that can give you the edge. You might not like it, but you cant say that its a bad item.

The testing was adressed to lonewolf537 and was considering his choice of sword of the divine not Ghostblade.

What about overall use of Yoyo? I dont find this item to be effective lategame.
Also, Highlander doesnt have a cd. Simple as that. If you find it to be on cd, when you need it, you did something wrong.
Also i cant say it's doubling the effect since diminishing returns will get in place on that movement speed. After reaching 415MS you get 20% reduction, after 490MS you get 35% reduction accualy wasting the statistics and gold itself. Even poping ghost is an overkill.
I accualy have no problems with MS on Yi. PD and Highlander with zerkers is enaugh to catch anything unghosted, and i have exhaust for ghost usage on my playstyle. If the enemy gets a bit too far away you can still Alpha strike to him again and again and again. I have no idea why ppl are so stubborn on that Yoyo.

Im usually not one to try and argue, but Ghostblade on Yi is very good.

If you use it, you arent CD dependant. Ghostblade and Highlander have faily close CDs, so its not like you would be wasting it. Having Ghostblade is like doubling the effect of Highlander. The only thing is Ghostblade doesnt refresh once you get the kill.

The other thing about Ghostblade, is its easy to build. It has fairly cheap items that build into it, and if you get first blood you can have it fast. I mean its not a bad item if you can get it early when Yi has the advantage.

EDIT: You asked if things have been tested? Oh yeah I have. In the build I have, I can get Ghostblade by LvL6, and hit Dragon. You might not use Ghostblade, but if you can get it early you are set early game.

OK for the Yoyo:
You dont get MS or AS permanently. only on active. For the cost of nearly 3000g there are better items that give passivly better stats. Now you are making yourself cd dependant since you have nearly 0 AS passive. 30 damage and 15% crit with 20 ArP for 2700g. Quite costy if you ask me. I woudl prefer even going Zeal+Brutallizer.

"do you enjoy constantly missing that dodge happy jax or that *insert squishy caster here* exhausting you so you cant hit him?"

Do you even have the idea how this item or any mechanic in lol works? or accualy tested things before posting?

i use youmuus for a variety of reasons, one being the armor pen, two being the speed and attack speed buff, and third being the added crit

as for sword of the divine being a no go

do you enjoy constantly missing that dodge happy jax or that *insert squishy caster here* exhausting you so you cant hit him?

Ok, since i main Yi, i will make my statement that Ghostblade is one of the WORST items for Yi. And totaly not a muss on any Yi build.

@ build.
Summoner spells. Well if you like ghost go on but imho its a waste to have it, you have highlander for MS increase. With Ghost you will just trigger diminishing returns on your speed and waste a spell. But that is personal preference.

Masteries. Well... hmm you eventualy get PD so why not standard 21/9/0 ? not that this HP/MP regen will save your ***.

Itemisation.
AS i wrote. I would cut the Yoyo out. Not that effective and you are becoming cooldown dependant. Also you are totaly ignoring AS. You will hit once a year. Farming creeps for gold that is required for a carry will take you ages with 0% AS and you will not trigger Yoyo just for farming minions dont you?
Ending up with only 45% AS is imho totaly wasting your double strike. You could swap those useless AD/lvl runes for Dodge/AS or even Mana regen runes. AD/lvl are not effective for Yi. You have your Wuju style for AD purpouses.

Desc:
"sword of the divine
a necessity for blind/exhaust heavy teams"
Total ******** - scuze my french. This is totaly wrong :)

"sword of the occult
if the other team is feeding you too much and its still early, pick one up in place of youmuus."
Or just put it into core and get rid of Yoyo at all? :>

"tiamat
decent for farming minions, but i wouldnt put any priority on this over your other items"
Agree. Only as a last item.

The only thing I dont like it Occult over Ghostblade.

Ghostblade is a must for any Yi build. Never give up the ability to stack Ghostblade and Highlander. NEVER!! Thats is a gaurnteed kill if you get Ghostblade by LvL6.

Other than that, +1