Yasuo Q doesn't hit when hit by cc

After playing many games with yasuo i came to a conclusion that his Q isnt that effective in team fights because over half of them are negated from cc effects. Although the Q directly lands on the enemy they take no damage and thus ending up with cooldown on Q for a direct hit. I also had an encounter where after the ult his q passed right through them but took no damage. Is this a bug or is it a hidden ability flaw that i haven't read about? Any insight on this?