Looking at your list of champs
Ahri - strong, but will be getting a nerf soon and you said you didn't want that
Fizz - he just got nerfed and some people don't like what it did to him. He's considered a weaker champ now.
Azir - He's expected to be nerfed and struggles a bit in the early game, but does scale well
Le Blanc - She's tricky to play and isn't great in the laning phase, but does have a strong mid/late game
Lissandra - She's been moving top lane more as the mana regen nerfs hurt her a lot, but she's viable with practice.
Zed - HE's not a great teamfighter and from what I've read doesn't have the best late game, but he's excellent at split pushing and has one of the best early games for midlane
Xerath - wish I could say something, but I know nothing about him. I've never directly faced him or played him.
As others have posted there are more. (Mid seems to have the most champions)
Nidalee - she has a tricky skill shot, and you have to learn 2 sets of skills, but she's versatile. Has wall jump ability.
Katarina - Can snowball, but also can be countered by hard CC. She seems to be a feast or famine champ and if she's kept from feeding early she can end up far behind the rest of the team and rather ineffective. Has wall jump ability.
Akali - often banned, but can carry midlane. Has no wall jump.
Annie - has a very short range and most of her damage is in her ult, but she can do well against some mids. she has no wall escape.
Morgana - with the right build she's very dangerous in the midlane. It can fit her better than support as she can use the gold from farming to purchase items. she has no wall escape.
Orianna - tricky to use powers with her floating sphere, but powerful with practice. she has no wall escape.
Cassiopeia - unless you like a weak early game and having to hit skillshots no, she has no wall escape.