Jacks of all trades have always been superior to one tricks in the game. Period. Yeah, there are people who do everything he does "better", but he does everything well enough also mixed with the fact that he can do everything. He can hard counter almost any top laner in the game simply by changing up the way his kit works. He has so many options to use to beat out so many opponents.
You're acting like just because there are champions who poke better or who all in better means that he's not somehow extremely strong. If he did all of those things like crap, then I could understand their argument, but good is good. When you stop to reflect on any negative in his kit, he almost always has an answer to them through one of his 6 abilities or can build for it someway.
Yasuo's an example of a champion who does a lot, while so many champs do individual things better. It's the fact that champions like Yasuo and Jayce bring so many cards to the table that it lets them be monsters whenever they please. They're extremely safe picks because both of them lack fundamental hard counters. They have hard matchups, sure, but at the end of the day the design of both of those champions is to make "hard" matchups simply skill matchups at best. It's not like playing a Veiger into an Ahri where no matter how skilled you are, you're likely going to get shit on. Yasuo and Jayce can outplay hard counters with little consequence.