Master Yi in Ranked?

If you use smite-tp and splitpush all day you have an almost free card to platinum. There you have to invest some time into learning Yi on a higher mechanical level but he is usable up to challenger w/o any problem.

It works.

~have fun

It works if enemy team doesn't have tons of cc. But don't be fooled - Yi is a very difficult champion.

works in ranked play, even in high levels, but you're going to have to work extremely hard with him to succeed past a certain point. Once players start warding, counter-building and counter-picking more efficiently, you're going to have to be on point with your Q timing and strategy (e.g. knowing where to roam, knowing which abilities your opponents can and can't use) to make him work, but if you do, you'll be able to carry games.

only works at lower elos

He does work from what I've seen, however there are things you have to be wary of. In low elo, he dominates because he's easy to snowball off a bad opponent. In high elo, he is an exceptional hyper carry that works well in solo queue. HOWEVER there is a significant fall off in middle elo, which is the point where most Yi players can no longer rely on their opponent screwing up and feeding them, and the enemy team is more coordinated in shutting you down, but you also have yet to master the split second timing that he requires to be successful at high elo.

That is why people say he sucks outside low elo, but there are also players like Cowsep who main him in master tier+, because if you don't have mastery of his mechanics, your opponents can give you a really rough time from anywhere between high silver to Plat.

Just a disclaimer, I don't play Yi much, but this is the generally accepted perspective on how Yi works (which is why people in Diamond know when they face a Yi it will either be easy as heck or the most annoying champion they've ever face).

I have a friend who made plat 4 only playing yi :)

Works easy until Gold, if you wanna get Platinum then you need some skill with him. But totally playable in my opinion.

Yes, not even frozen heart counters him