Problem with Akali is not her W
It's her passive.
Yeah i know having a assassin who uses "hit and run tactics" is a great fantasy, but its not working in the game.
If Akali hits you with Q she can run away with 500 MS which makes trading back impossible, and when she is in a safe range she gains another speed boost and empowered attack, which makes escaping from her impossible and you cant trade back since she will win harder if you stay closer.
Change her passive to a 15ish second cooldown and remove ring system, so we can have a healthier assassin. Or just remove speed boosts.