Picking Yasuo mid is like adding an extra ADC and support to your team....

I say this because Yasuo does the same thing an ADC does. He deals sustain damage, takes towers and even shreds tanks. Hell, he even has more range than most melee champs and there was even a time when he didn't gain MR per lvl, just like an ADC.

The only difference role wise between him and a regular ADC is he is a melee champ. And being a melee champs grants you additional tools to survive like his windwall, dashes and massive AOE CC.

But the thing about those additional tools is that it pushes him in the same role as a support to some extent. His AOE CC supports his team if he gets a 1-5 man knock up. His ult up can extend the duration of short knockups like Diana E from 0.5 to 1 second. It can also extend knock ups that are about to end by a further 1 second if time right.

But thats not all. His wind wall is so wide at max rank soaks up tons for damage in team fights. While he isn't directly/ or intentionally shielding his ADC/team like Janna would, that wind wall soaks up more damage that any support shield would.

Don't forget his AOE CC allows for ADC and team to deal additional damage.

So while Yasuo isn't intentionally trying to perform the role of a support, he is supporting his team as a byproduct of his inherent kit.

At the end of day, picking Yasuo mid is like adding an extra ADC and support to your team....