Why is Yasuo allowed to have just so much?
Tryndamere, Yi, and Fiora have basically never seen competative play.
The limited pro play Trynd and Yi have seen was with their no defunct AP builds.
Melee carries have gone through a lot of problems with being useful champions due to the massive disadvantages that come with being melee and being squishy.
So Yasou got a lot of tools to deal with said dissadvantage.
Infinite dashes, DOUBLED CRITRATE, a wall which renders 80% of all ultimates in this game useless AND has low CD, AoE Knockup, insane amount of Armor Penetration, Invincibility, NO MANA COST.
He can only dash once to a specific target, so his dashes are limited to the number of hostile units he can dash to.
80% is an extreeme over-exageration. There are a wide range of melee-range ultimates in the game, and any buff-reliant ultimate is not a projectile. Darius, Garen, Fiora, Renekton, Nasus, Soraka, Karthus, Zed, Akali, Master Yi, Tryndamere, Poppy, Rengar, Lux, Vel'Koz - the list of champions who can bypass Wind Wall with an ultimate is pretty extensive and more for me to list.
Armor Penetration only applies to Bonus armor, it doesn't hit base armor. You need to pack a lot of armor before Yasou's bonus armor pen steroid kicks in, and he needs to land his ultimate to access it.
Yasou doesn't get invincibility. I have no idea why you'd list that as one of his traits. He gets a ~meh HP shield and wind wall.
"But he's so squishy in lane QQ" - what does that matter if he can block poke at no mana cost?
100% useless if he's lanning against another melee.
What does it matter if he's 1/6 in lane if he still can counter a whole Syndra combo and take 40% health or more of a half to whole team.
If you're entire team derps out hard enough to get 5-man knocked up you deserve to lose a team fight. Pretty much every team comp is going to punish you for that kind of failure.
Also, most champions worth using bring some level of presence when they're behind. If that wasn't the case the game would pretty much be over after lanning ends and the victor would simply be whoever has the most gold from that point.
Seriously, this champion is just broken. He has to be reworked.
Or at least his infite dashes and wall have to be brought to level which isn't pure insanity.
Most fighter/assassin champions have very extreeme defensive mechanics. Jax has 100% dodge, Fiora and Fizz and Yi get untargetability, Tryndamere refuses to die, Poppy gets invulnerability and immunity to CC.
Yasou isn't out of line in terms of mobility or defense for his archetype. His mobility and defense is mostly just geared so that he actually wants to team-fight, rather than causing a ruckess split-pushing in the hopes an enemy will 1v1 him.
His wall being his predominant defense is also far less than pure insanity to deal with. You can walk around it, through it, or away from it. You can fire projecitles around it, bait Yasou to come out of it's protection, and use pretty much every single trick in the book revolving around positioning to deal with his wall. It doesn't move with him like Poppy's Diplomatic Immunity.