Not like Rengar exists, who doesn't even complete his jungle item until later in the game.
Let's not forget that many in the community don't even know how to balance.
Recall Irelia's nerfs? When they were announced, people went on crying how they aren't enough, and how she shouldn't even get the compensation buffs on other parts of her kit she got, and how she's still gonna be the best champ in the game and the nerfs are, as you called the suggested nerfs from that player, placebo.
What did the nerfs end up doing? Irelia got gutted, by the nerfs players said aren't enough.
You disregard OTP suggestions because of "bias", but you also need to keep in mind that a main who suggests nerfs also understands that champion better than a random who played the champ 2-3 games, and the OTP also wants the champion to be playable, not gutted. Talon's nerfs from PBE are ok, but just that, it doesn't do much, exactly as the guy said. It reduces Talon's power if he doesn't buy Tiamat, but if he does, then nothing happens.
You need to consider how a nerf will impact more than just a champion's kit. Let's look at Taliyah's nerfs, 2 sec on her Q early. People cried that mid lane Taliyah is hurt more than jungle, while it's so untrue. 2 sec more after each cast, depending on a leash and elo (lower elos give worse leashes, seen Garen's not want to tank blue because "it would harm their lane"), she needs around 4-5 Q's to clear Blue, Gromp and Scuttler. That would be 8-10 seconds extra time, doesn't sound much, but that means she takes extra damage from the camps early, can be invaded easier, has both worse ganks due to her extra time in the jungle and lower health due to taking longer to kill camps.
A small nerf can have a huge impact outside of the kit, so don't just disregard the nerfs an OTP suggests as placebo nerfs, as they could have a huge impact when one sits down and analyses the situation in all aspects.