the problem is that lee sin doesnt have counterplay. its basically a question of, does his player fuck up or does he pull off his combo clean on a gank? you, as his opponent dont have a say in the matter if you can avoid t or not. if he doesnt make a mistake then there is nothing you could do to prevent getting shit on. even if you played the situation perfectly yourself.
You can outplay any part of it. You're able to dodge his initial part of his combo, if nothing else, and that entirely shuts down his potential. If he starts to go in, you start running. Or you use a stun mid-dash. I'll say it now, Ahri is the perfect counter to Lee Sin.
lee sin when optimal played doesnt give his opponent room for counterplay.
Same could be said of many champions. It's more true of some others than of Lee.
is the perfect example of this.
is close behind. Fiora's skillshot is harder to avoid, and Riven has basically nothing that counts as avoidable, since her ult is stupid-wide. A perfectly played Riven leaves you no chance to win. But even a perfectly played
is impossible to beat, that's the definition of perfectly played.
its the same issue with other flash interactions and why those champions got nerfed into the ground. they turned skillshots into direct target abilities by flashing onto the hitbox of their opponent mid dash.
gragas mid body slam flash, reksais flash into a knockup, or shens mid dash flashing into a taunt.
with lee sin its a similar problem. he easily manages to get into point blank range for his q, which makes the ability being a skillshot mute, and is able to flash into position for an ult and to adjust the direction of the ult. the mini cc attached to the kick doesnt even allow his opponent to react with a flash himself.
Gragas's is a heavy stun, with an AoE knockback. Lee can only kick one person. That leaves Gragas free to walk away, and Lee very susceptible to a Leona combo.
Rek'sai is a champion with a very easy escape, and, I do believe, has another AoE. I can't be certain, though, because I haven't seen Rek very much.
Shen's taunt also comes with invulernability, and can't be body-blocked…seeing a theme, here? Lee's kit leaves him very vulnerable. Shen, Gragas, and Rek'sai all have some saving mechanism in their kit, typically in the form of AoE CC. Yes, I know Lee can cripple the enemy team, but they're not silenced, so they can still stun and crush him.
basically his ward hop into flash + ult + q, q cant be avoided on almost every single champion. there are only very few exceptions.
its these unavoidable flash combos that make lee insanely reliably on his ganks.
Few champions can avoid it when he starts, true. But all you have to do is go: "Oh. Lee's about to gank me. I should stay out of his range", and then do so. The counter to his F+W+R combo is 4+rightclick, or "ward and move", as the pros call it. So it's not really unavoidable, it just takes prediction. It's just like predicting Riven flash-E-W ing you. Sure, once she does it, there's no escaping, but you can expect and predict it.