I mean sure he is kinda squishy but many bruiser/assassins are. He has poke and he has no mana. He has utility and good anti-poke. He has CC too. He trades nothing for his mobility. So I suggest either he has energy, a charge system, or something for windows of opportunity where he cannot dash and enemies can react accordingly.
Don't downvote me into oblivion, I'm not saying Yasuo is broken at all. I am merely saying he trades nothing for his mobility. If you can provide a good argument on what he does trade, then sure I'll change my mind.