Give simple champions counterplay. I'm not saying make them difficult just make them have some skill besides do I win the fight or not. Some champions on the list would be: 
If you disagree let me know why.
Hotarµ1 votesSigh. I know this is going to get downvoted or just ignored, but:
Don't get hit by bandage toss. Build MR, ward sidelines so he can't flank with good ults. Bully him early if jungling.
Very immobile glass cannon. Bully him with fast moving champions and dodge his stun-skillshot to avoid burst. Don't stand close together with your team.
Same as Amumu.
Kite him, back away if you're the villain. When teamfighting, hard CC him and shift focus to other teammates so he can't destroy your backline. Grevious Wounds.
Grevious Wounds above all else. Same as Garen.
Shield the one champion you know he's going to burst (generally your ADC.) or block his burst entirely with Shen's W / Zhonya's. Ward safely to avoid him engaging.
Kite him / knock him away when he uses his one engage. Bait out a counter strike and stop him from AOE stunning your team.
Probably the hardest champion to counter on your list. Ward properly to avoid good engages with her ult. When she does engage, knock her away or hit her with hard CC to stop her focus on your backline.
Don't group together in teamfights, stay spread out but just close enough to engage after he ults. Armor pen (Black Cleaver) and magic damage generally destroy him if you have to focus him.
Easiest champion to counter on this list. Hard CC him once in a teamfight and he's dead. If he has Sash, another round of CC will take him entirely out of commission. Exhaust, hard CC, grevious wounds, and wards all destroy him and his engages.
Deny him stacks early and force him to splitpush while you punish his team in 4v5s. If you can't punish him, knock him away or lock him down with hard CC and try to peel for your ADC. He's an immobile juggernaut, don't let him in close.
Generally falls off late game, but his early game bullying can be offset with ganks or building tons of armor.
Ward properly, don't let him snowball early. If he does ult in a teamfight, back up to deny his engage (he needs vision of his target to actually dive at them) and since his build generally consists of lifesteal or attack speed, grevious wounds and armor will disable him.
Denying him early and grievous wounds will demolish him altogether. If you're still struggling, shield your backline and try to disengage until his ult runs out.
Engage / disengage surrounding her ultimate. If she's about to ult, back up so she can't pull you together. If she's just teamfighting, body block her fireball to protect your backline. Also, grevious wounds and armor pen.
Hard CC. Functionally the same as Yi, don't let him snowball but if he does, CC, CC, and more CC.
Walk away from him. Seriously, just kite or hard CC him. I have M7 on Udyr on another account, and Vayne, Tristana, Caitlyn, and Quinn can all destroy him at any point in the game. Don't let him focus your backline.
Grevious wounds, hard CC. Similar to Nasus, he's not very mobile. He's a juggernaut, don't let him snowball and try your hardest to deny him early. Alternatively, splitpush to take his focus away from teamfights.
Frosted Tips1 votesI feel like you think I think they are all strong. No they are all either terribly weak or super strong because they don't have enough counterplay. Because of this they are not balanced. So when they become strong they abliterate everything look at Garen and when they are weak they do nothing look at Hecarim.
Hotarµ1 votesExcept almost 75% of the champions you listed are, at the very least, viable. None of them are glaringly weak or overly strong.