Diana needs a rework to be useful at all.
I know what's not right. She suffers from a really weird syndrome called "pre-6, callmeuseless". That means she can't do anything meaningful before reaching level 6. This has been her issue for years and Riot has completely forgotten their beloved champion (or is it not?). She's bad in the jungle cause her ganks are bad pre-6. She's bad in the middle because every smart player can out poke Diana in lane and get ahead. It's a free lane for the opponent 95% of the time!!! She has even worse laning phase than Akali does!!!! Why has this been like this for decades?!