There are some champions are just so op, when we see them we will lose 100% to them. They might have high skill caps but still, people who do play then almost never lose. This is the list: 
. These champs I have never seen bad, are an exception to this but still needs Nerf. So just saying, i hate seeing these champs and never winning against them. SO PLZ RIOT NERF THEM!!!!!!!!!!!!
Jax lost most of his tankyness from a nerf, yasuo got nerfed continuously for like 4 patches straight, base damages on nidalee were nerfed, and Le Blanc lost her silence her while back with a nerf. Half of the champs you listed already got nerfed. For Darius, if you kite him he's a goner with 0 mobility. So the only ones that I even mildly consider borderline OP is Fiora, Akali, and Fizz.
Yi is a noob slayer. Gotta know how to deal with mechanics if you want to deal with him.
Darius is a push over. looool. Nerf Darius? Good joke.
Fiora is already getting nerfed.
OpieOP ? 
Nerferino plex
