I kinda understand what you mean, but.. can't you just kill him?
Killing someone is not counterplay, because it is true for all champion's equally. The only arguments would be for Tryndamere and Karthus, since one cannot be killed and the other can temporarily benefit from death (Infinite mana, ult can't be interrupted). Specifically killing people is not counterplay to a champion's kit. The complaints are less that Yi is super OP, it is that players have no option to directly respond to his kit itself.
CC does counter him in general
CC counters all squishies, so falls under a similar category of the one above. However as I noted cc does counter a single part of his kit, his W, since it stops his channel. The interesting thing to note here is that the way Yi is set up gives him more opportunities to outplay his only form of counterplay than opponents have vs him.
Killing Yi is hard due to his W's healing and damage reduction, specifically it is very strong vs burst. This means that you have to break his W with CC. However if you save your CC to interrupt his W then your ability to directly kill him drastically goes down. His Q also lets him dodge many abilities, CC included. Basically Yi's W gives him more ability to play around opponent's CC than opponents have to play around his W.
Imo, there is just nothing to counter
Which is the issue.
I wouldn't really say he has no counterplay because of it.
Directly counteracts your previous statement.
It is also worth noting that his E and R let him ignore a major form of counterplay, item builds. Yi gets quite a bit of true damage, and his ult "can't be slowed" also makes him immune to attack speed slows. These two effects massively decrease the effectiveness of the items that normally would be best against him. By building Botrk he can cover flat HP, the one stat that is fully effective against him.
Keep in mind that player's issues isn't beating Yi, it is being able to play around Yi's kit.