Diana can't lane against any ap mid in the current meta.
Diana, a champ that doesnt snowball very well, is completely useless until you have fully stacked rod of ages, nashors tooth, lucidity coots, and rabadons and also has probably the shittiest laning phase in the game. Diana gets zoned off of minions so easily by any mid laner because shes melee and almost every other ap mage in the game is ranged. Diana also has EXTREMELY situational mobility and doesn't do nearly enough damage to compensate for it. You have champs like anivia that just R, E and they can blow you up. OR annie, who can half shot you with just q and w. With Diana, even at full build you have to land Q use R W E and use R again and it's not even a guaranteed kill. With all the shit riot has done to all the other mages Diana simply cant survive anymore and is almost useless in lane. If riot is going to make every other mage be able to use two spells and blow you up, Diana should do the same.
Here's a few examples.
R+E=Dead
R=Dead
Q+Spam point&click E=Dead
R+E=Dead
Q+R=Dead Akali has the same concept as Diana but out damages her by a shit ton
Any spell=Dead
Q+E+w=Dead
These are all according to late game stats and killing a person with about 2.2k health ish
So why is it that Diana has to land a skillshot, use R, W, E and R again bearing in mind that if that doesn't kill the person she will get blown up instantly. The purpose of being an assassin is to actually KILL THE PERSON QUICKLY AND WITHOUT FAIL.
Dont comment some shit like "He's bronze, he obviously doesnt know shit about the game and we shouldnt treat him like an actual person"
If you're going to be a dick and not have a civilized conversation, GET THE FUCK OUT NOW. I am actually interested in what makes Diana equally as powerful as every other mage in the current meta, because i honestly cant find anything.