The Bottom of the Barrel
These are the 10 least played champs in the game. If you'll notice, most of them are AP champs. 4 are dead junglers. I am not sure why Skarner is dead he's still pretty good. None are top laners or supports as primary roles.

Skarner has the 69/141 wr and Sol has 12/141 so they do not really need work. As for the others, they are in the bottom 20% in win rates. Most of them need quality of life changes. Azir is nerfed hard because of abuse in high elo. Cass and Kali also have pretty high skill caps, but could use a buff of some sort. Elise is a weak version of Nidalee, who is not strong either. Corki is just very weak. Ivern is boring really. He does not do damage and if played incorrectly is completely useless. Plus the nerfs to shields were not in his favor. Rek is a wreck. No one plays her because she is terrible. RIOT took her global for some reason. Now she sucks. Kass is a tough champ to play and his counters are strong now, so RIOT would be in a tough spot buffing him. 'Kassawin' still haunts older players. Back in a day when he was a 98% pick/ban champ. Kass has a very quick 1 shot burst if fed and i don't think RIOT wants him to be too good again, but he needs some sort of buff even if it is meant to be temporary.