Haha yes, fair enough. All of these champions have real problems from that perspective.
So the question is - does Riot need to rework about 25% of their champion roster (others not above included obviously), or do players need to learn to play against these type of champions?
I think it should be a combination of both, i.e. largely they just need to really increase the cooldown of these abilities to give enemies real windows of opportunities to take advantage when they miss. There's nothing wrong with giving an ability like Thresh' hook a 28 second cooldown at rank 1 (and honestly I'd want to see his lantern's cooldown increased too).
Or for thresh specifically, it'd be really cool that if he misses his hook entirely he loses it and his auto attacks become melee (he keeps it if he hooks a minion though). That'd be interesting counterplay.
For blitz a missed Q should result in him standing still for a full second while he retracts his arm.
Yasuo's cooldowns are just too low.
Lee Sin I honestly think is fine overall.
Increase the cooldown on Morg's Q, or decrease it's hitbox.
I'd be fine giving these champions numeric buffs to make up for these nerfs if needed, but I think this would give them better counterplay.
Illaoi though, still haven't had a problem with her and she's new. Probably just needs some getting used to.