The 10 ban system exists. Also yasuo is not by any means an easy champion to play. You just got to cc him and focus him. That's how you beat him. I always ban yasuo if I don't know who else to ban. Also I bet of you played him right now, you would learn quickly how big of a trashuo you probably are. He's also probably the most gold efficient champion because of double the crit chance. Also if you can set up counter ganks, you can stop the enemy jg from ganking his lane. Also the all he needs is farm part doesn't apply. Yorick, nasus, Jax, tryndamere, or any other super hard splitpushers fall under that category. Also you and shyvana for jg. Sure yasuo can splitpush but there are better options. He rewards agressive play and that can be dangerous. If he's top, pick someone like malphite. If he's mid, pick a battle mage and build seekers as your first item.