Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Threats to Yasuo with this build
A brief overview of Yasuo's laning
Engage for heavy poke, make sure you have an escape minion and or wind wall depending on who you are laning against. When not engaging for poke stay behind your waves and play passive qing minions up the front and then throwing out your 3rd stack q for heavy poke pre-6. Yasuo has very little to escape with so avoid making yourself a target by over extending. When the enemy laner is low enough then all in if it is safe.
Maxing alternatives and rune page alternatives
Placement for early ability points could be Q, E, Q, W against Laners with non-ranged auto attacks and primary damage abilities that cannot be wind walled for example Kayle. Also you can max e first, but only if you intend to farm passively against a harder match up that you can't poke down.
Critical damage reds are also viable but less reliable then armor pen reds as they give you a better early game.
A brief overview of Yasuo out of Lane
Don't go in on tanks unless its a free kill or the entire enemy team other than the tank is dead and you have backup. Only ultimate knockups on squishies, preferably groups of squishies. Don't go in on every knock up you get you have plenty of time too catch them on your way down after you have assessed the situation. Try and 1v1 the enemy adc a lot your wind wall makes you a direct counter to most adc/marksman type champions and therefor gives you a lot of free kills.
Why build trinity force and phantom dancer over tank and shiv?
Trinity force is a great item on Yasuo, in fact almost as good as infinity edge. Yasuo's Q procs as an auto attack meaning that sheen procs on it as well and scales with 200% of your base AD when you have trinity force. Furthermore the crit on trinity force in patch 6.11 will no longer exist and will have more attack speed instead making it even better. Phantom dancer is better for Eing fluently and 1v1ing people as the attack speed is just better in general and makes your damage more consistent.