Why is Talon allowed to exist in his current state? In this current one-shot meta, I'd have to say that Talon is probably the worst offender in terms of the problems of insanely high damage. There are a multitude of problems with him right now:
1. Passive does insanely high damage (200% Bonus AD ratio). While it does a ton of damage, Talon rarely even needs to proc it thanks to the high damage on his other abilities, so it's really only useful for getting that juicy first blood needed to scale uncontrollably.
2. His Q is a very long targeted leap that can be very frustrating to play against thanks to its fast travel time and unexpectedly long range. If you're already in melee range, the damage is massively amplified to the point where even at level 1 (if he takes Q instead of W) it alone does about a third of the laner's health.
3. W hitbox. Please fix it. The ability really isn't that bad otherwise, although the slow can be annoying, but fix the hitbox. It's probably the most misleading hitbox in the game.
4. E needs an actual cooldown. Not a increased per wall cooldown, but a cast cooldown. Talon, especially early game, rarely needs to jump over the same wall every couple of minutes, and this ability makes him untouchable when he wants to be. With its 2 second cooldown, there's not any way to catch him except hope he already wasted his jump on the wall he's going to.
5. Stealth is annoying, and it doesn't help that Talon's ult also gives him a burst of movement speed. The damage on this is also incredibly high if you allow the blades to converge on one target.
Overall, I feel like his passive early on and his Q and Ult throughout the game are the biggest offenders in terms of his massive damage output. Before anyone says "this guy is just complaining because he got destroyed by a Talon": you are correct. But my last game isn't the only reason that I'm posting this, it just inspired me to. I have had many problems with Talon for a while now, and when it's not Zed mid lane, it's him. Something needs to happen with him, as his current state in this game is not healthy for anyone.