Yasuo is a very poorly designed champion
When I started playing this game at the end of season 4, LeBlanc was the first champion I bought. Naturally that led me to play a lot of games mid lane before learning other things. Now, say what you'd like about LeBlanc, but at the very least, her burst and killing ability are both limited by cooldowns and mana. This goes for most midlaners as well, most of which are mages, and or have some kind of resource to manage. Even champions that use Rage as a resource are still limited in ability by cooldowns.
But Yasuo? He has NO resource to really manage, his cooldowns are mindbogglingly low, all he has to do is move around for a shield, he gets double crit chance, ANOTHER shield that blocks almost every project in the game, his potential in mobility is limited only by creeps, his ult automatically recharges his passive shield, and to top all of that off he can IGNORE 50% of your bonus armor after ulting for 15 seconds??
I don't really think it's a good idea for newer players to pick a champion like this up because he teaches no real discipline. None of the habits you learn from playing Yasuo can be carried over to other champions, save maybe for Zed. But even Zed has to manage Energy as a resource. Going into season 6, I really think Riot should take another look at this champion and at the very least tinker with him.