Is Yasuo Completely Useless?

I've been playing Yasuo almost non-stop for the past few days, and my gosh I can't do anything with this champion. I know he's difficult to play, but it just seems impossible for him to be useful. He does amazing damage at full build, but he's as fragile a glass egg.

I've tried the traditional build, the Trinity Force build, tanky/brusier build, lifesteal build...everthing. None of it works. He can't teamfight to save his life, he's just too squishy. He gets blow up immediately upon using his ult. It seems completely pointless.

I've tried even doing what his champion spotlight suggested, building some tank items, but they don't help at all. He STILL gets destroyed the instant someone even bats an eye at him.

I've gone from mastery 1 to 4 in the span of only 2-3 days, and that's mostly from losses or getting hard carried. I've been an undeciding factor each time. I can't do anything with him.

Am I just bad with him (which is completely possible)? Is this meta unfavorable for him? Wasn't he nerfed really harsh shortly after his release, is that the problem?