i want to main a high skill cap champion, im thinking Azir, Zed or, Yasuo?

None of those.

Yasuo is always banned and you're an asshole for playing him.

Zed is useless and does nothing for your team composition but net kills.

Azir is so broken you should just wait for a rework.

Go main Riven or Gangplank or Vayne or Twisted Fate or something else with a high skill cap.

Meepo

Can easily outlevel everyone due to getting exp fro mseveral different places at once but if one dies all die

I'm hesitant to say Yasuo due to his ban rate and the fact that I main him myself. But go for it. He's incredibly fun and challenging. Make one false move and you are down for the count.

Zed is a much safer pick, as he has multiple escape options to include an ultimate that makes him temporarily untargetable. He also has extemely good wave clear, and an instant all in that'll leave most people screaming at you.

Azir isn't necessarily good right now, but in the right hands he is still a nightmare. He has great mobility, and isn't banned at all right now.

I'd say Yasuo, but then again it's because I like him so much. Just play safe in the mid game, you tend to fall off for a little while until you can finish your core. The early game is surprisingly good if you can land all of your intended damage on an unsuspecting laner. But if you don't have a lead by the 10-15 minute mark in the lane, just back off and farm. You will start to lose in most fights that you think you have the upper hand.

I take it you have mastered the art of game knowledge?

imo the champion with the highest skill cap. literally all skill shots save for autos, forcing you to play to the best of your ability at all times. no mobility, high mana costs so you have to make the most of your abilities (even with your passive.), squishy as hell so you can't make that many mistakes, and without level 6 killing people is super hard, even WITH level 6 its one of the hardest things to land imo. on top of that he's not even that popular/FOTM so nobodies gonna bitch at you for playing him. he's pretty fun as well if you can play him right.

Azir, because he's the only one of these champs who actually takes skill.

Azir is dead, Zed is not that good unless you one trick him, and Yasuo can be really good if you main him. I still think if you one trick Azir you can do good as him, but he is pretty much dead as a champion. He has one of the lowest win rates in the game (42.6%). That is just horrible. He is also (in my opinion) the hardest one out of those three. Zed is kind of like Azir but more rewarding and less... dead at the moment. He still sits at a crappy win rate (46.91%) but if you are good at him, you can still do quite good. Yasuo, however, might feel bad when you first play him, but once you understand him completely, you can just ruin everything and win every game. In my opinion, he is probably the easiest out of the three to play at an average level and master, but is also VERY rewarding. If you want to play him at mid lane, he sits only at 49.87% and at the top lane he is at 50.27%. This might be because noobs play Yasuo thinking he is easy but then change their mind.

TL;DR: Azir is not that great at the moment and is the hardest out of those three. Zed will feel terrible when you first play him. Yasuo is MAYBE the easiest out of those three but is the most rewarding if you main him. Yasuo is most likely your best one trick champion.