Reworks and Buffs, IMO

Reworks: Jax- His kit is pretty outdated and he doesn't really have anything special about him besides having massive attack speed, but he can barely hit the cap and Kog'Maw is more well known for that. I think they should change him altogether. Master Yi- Self-explanatory.
Malphite- He is only known for his ultimate and the rest of his abilities besides the E ability(slams the ground) doesn't really contribute nor teach much. His Q is just there for poke and chase, but it sucks.
Udyr- His kit has nothing special about him, and he doesn't really bring much to the team besides being a tank with limited crowd control. Urgot- Self-explanatory Twitch- I feel like his ability to do massive damage in teamfights is okay, but I feel like his W ability kind of sucks and his Q ability gives him too much reign within his onslaught. Karthus- The kit is a bit outdated and he really hasn't seen much play in any tier because of the complications within his kit. Fiddlesticks- His kit is a bit outdated and he really doesn't teach much. Soraka- She's a bit too simple for a support and isn't very complicated in terms of her kit on paper. In addition, she doesn't really teach any skill besides peeling using heals, but all you do is press W and R. I feel like the R ability has to change like she can heal 3 people massively or offer a shield based on groups, like Taric's ultimate. Buffs: Azir- He is barely seen and I have played him to an extent to compare the before and after(pre/post nerfs). Kalista- Her playerbase is too low because of her massive nerfs. Zed- He feels completely underwhelming and can't really carry so he isn't a force in this meta. Yasuo- He's basically in the same boat as Azir because he needs to wait for his items to do damage, and he doesn't offer as much as the mages do nor the carry potential. Riven- You barely see her anymore. It's just like there's no reason to play her while there are these easy-to-play tanks. Fiora- She isn't in this meta. It may be for tanks, but at least make her an option.

That's all I could come up with now.