Everything you wrote is just completely wrong, and here is why:
Her early game has always been shit
Her new passive with TD shreds tanks to bits which makes her playable in toplane as well as mid, and she has a much easier time sustaining. I regularly take out almost 40% of an enemies HP in A SINGLE TRADE which takes half a second AT LEVEL 1. Attack minion to get to second part of passive -> Q -> attack with 2nd part. Hit + Q detonation + passive + TD is an insane amount of burst, and she can repeat it over and over.
The blink on her W offers escapeability and further outplay potential guarding against early ganks
her mid game is about the same as it was before
Also wrong.
She now starts with full stacks on her ult as soon as she gets it, the "run through" mechanic and W blink allow more juke against CC, and her midgame burst is delivered much faster. The passive being used on turrets means shes a pushing threat even without building lichbane.
The difference now is that her late game is horrid.
Uh huh. No, it's not.
Shes one of the easiest to play anti-carries in the game, a great duelist, has enormous outplay potential and can splitpush on her own in return. As long as she doesn't try to engange right into the enemy team 1v5 on her own, her late game is absolutely great.
The only way I've been able to do well with akali after putting 200k mastery points on her is to build gunblade, zhonyas, and abysal and getting two tank items and boots. She's not a good AP Assassin anymore.
The only thing this proves yet again, is that mastery points are not an indicator of skill, but only of playtime. I have less than half the mastery points, and I destroy on her.
Maybe you should spend some time watching good Akali players.
https://www.youtube.com/watch?v=JE2L5lAlvMQ