Stop neglecting Diana. She needs some changes.
Diana's kit is super unhealthy right now. Let me begin by saying, IM NOT A DIANA HATER. I have 400K Diana Mastery points on my accounts in total. I love her and have mained her for a l-ooooooooong time but her current state is extremely toxic.
Diana needs a Kat-Style rework. Diana's kit just doesn't quite sit right in this game, with all of this CC being added left and right. For such a terrible early game, her team fighting abilities are mediocre. Yes, she can 100-0 the adc (I'll get to this problem in a second), but then what? She'll just get CC'D and Murdered. People's main counterargument to this is that Zhonyas can just be bought, but unless the enemy are trash, she isn't going to escape a crowd like that.
A bigger problem with diana is that she does too much damage way too quickly. She needs her damage delayed, like kat for example. I'm not going to going to go in depth because everyone knows what I'm talking about.
Diana's kit is also extremely lackluster; it's old. I compare it with the old akali/kat kits a lot because it's almost just what they used to be. It doesn't mesh with the new kit, and it certainly doesn't reward players for being good at her.
So where should Riot start?
Well for starters, Figure out what she is. You're all trying so hard to make her a Fighter, but she isn't, and will never be. No matter how much DPS Damage riot will add on her passive, the current AP items just won't support a squishy AP Fighter like her, Especially one that would rather do so much more burst than DPS. Diana will never be what riot intended her to be, but that's fine. Her play style, and everyone plays her as an assassin. Now it's time to give her the assassin rework she never got.