To be honest Yi is a scumbag champ

Not that he is OP or anything. He is just impossible to balance period. Similar to Fizz.

You can thank these effects:

• After landing 3 basic attacks, Master Yi's next one within 4 seconds strikes twice, dealing 50% AD bonus physical damage which applies on-hit effects and can critically strike.
• Master Yi becomes untargetable over Alpha Strike's duration, and can critically strike, dealing 60% (+100% bonus Critical Damage) AD increased damage to all enemies. Basic attacks reduce Alpha Strike's cooldown by 1 second.
• Champion takedowns reduce the current cooldown of Master Yi's basic abilities by 70%.

Now, you may say Yi's counter is CC. It is, but only if you can hit it. That's where his Q comes in. It removes that and if he lands essentially 4 aas (which is actually 5) he gets a 5s CD reduction on his Q assuming he hasn't somehow killed someone from the Q with crit + 4 1/2 aas of damage + true damage. Yi's true counter is just straight burst or untargeted/on target CC. Skillshot CC misses him most of the time due to his Q. On target CC is basically gone.

I feel like Yi needs a kit that is less focused on resetting his main abilities and more focused on resetting his ult to restore him to a balancable state. That or his alpha strike needs to be looked into as it breeds similar problems as Fizz troll pole.