Things that are absolutely bullshit in League of Legends - Yasuo's wind wall.

Most of Yasuo's kit if fine, standard toxic assassin stuff. His ult is super annoying and weird but you can live with it. The wind-wall however...:

The wind wall is broken. It is way to powerful (sometimes). League of Legends is based on the idea of not having to hard counters, so that skill matters more than pick.

The wind wall deletes all enemy projectiles that go through it. Basic attacks, skillshots, "no-skill shots"... The ability will delete anything in contact with it's hitbox. And it's placed just about instantly. Result, Yasuo can put down his wall when he sees a dangerous spell going towards him. He can then stand inside this wall to be completely immune to most ranged attacks. He can dash out, and walk or dash back once projectiles are going towards him.

The cooldown is currently 18-26. There is no counter for projectile-based champions, so they will only have a chance during this downtime. It works, but it's a really shitty mechanic.

Reasonable other designs:
Fizz's Playful makes him untargetable for 0.75 seconds. It performs the same role, helping an assassin avoiding damage. Fizz has to stop moving, have to time it well and will only protect himself, making it annoying but reasonable.

Braum's Unbreakable - Released soon after Yasuo, it uses the same blocking projectiles mechanics. It however removes the first projectile, the rest will do (reduced) damage to Braum. CC is still applied. In addition, Braum's shield is much smaller and will only work from one direction.

Ideas on how it should work:
Making projectiles become AoE on the wall - Will fix most of the issues and punish bad usage.
Add a delay and wake it only work from one direction - Will make it reasonable and counter-able.