Absolutely loving all the red posts! So I thought I'd throw this back up here.
Diana's issues right now are that she has too much damage in her w/ult, that it's more effective to build her as a glass cannon one shot and all of the cleave mechanics sort of go to the wayside. She's also in an awkward position where she isn't really tanky enough to do extended fights, but if she builds items to compensate her damage suffers too much.
So I thought about ways to fix this, and this is what I came up with.
Passive: Fine as is, but numbers might need to be tweaked given the other changes. I would like to see the attack speed back in this kit.
Q: Fine as is, one of her most notable skills.
W: Lower the damage, and increase the shield (damage can go back up if she needs it).
E: Move her ult into this slot, and take away the damage, but add an effect "her next auto after this ability will cleave". It still resets if it hits a moonlit target.
R: New ability "Starfall" She slams her sword into the ground creating a massive aoe that will slow enemies, and increase Diana's movement speed (can also increase allies if you want more of a teamfighting role). Diana's attack speed increases, and every auto she performs will cleave. I've been back and forth on whether this ability should also damage opponents. That's something that would probably need some extensive testing first xD.
Interested to see what you think!