I love the Akali defenders who are still trying tooth and nail to keep her OP.
The truth of the matter is and I've played Akali and awful lot myself (not as of recent as I tend to move away from champs that sheep associate themselves with) she is far too cost effective as a champ when compared to every other Assassin, Anti-Carry and general burst AP.
By cost effective, I refer to her stats and free gold passives not her IP or RP pricing, let me throw a comparison for you:
Akali vs Talon
I just thought I'd go with this one as Talon often gets a lot of QQ thrown his way as well, however unlike Akali, Talon does not have early game sustain, nor does he get bonus stats for free (he gets bonus % damage from CC but if you work it out, it isn't really a lot when compared to Akali's free gold passives) Talon's base damage for an Assassin aside from Rake is also on the lower side when compared to Akalis, thus he needs to build Armor pen to make the most of what he does have.
In a cost effective battle, Akali is relatively cheap to become powerful unlike Talon, Talon needs a Bloodthirster and Yomuu's Ghostblade, Akali needs a Rylai's scepter.
Straight away there is a cost disparity, Akali becomes snowbally off one completed item, Talon needing two, as late game begins to roll around, Akali can build a Lichbane to stay powerful and a Gunblade to grant her much more insane sustain which she will get since she is snowballing from the Rylai's.
Talon however needs to plan his build much more conservatively and can still lose his Thirster stacks if he makes a mistake. Since he is AD he needs to think about possibly grabbing more Armor pen to keep his damage cutting through armor and thinking about if he wants defence an infinity edge or a second thirster, Gunblade is wasted on him as he does not benefit from AP or spellvamp.
So again, further disparities are shown in that Akali can pretty much no brainer it for more damage and Talon has to think about getting armor pen and defence to keep his power levels up to scratch, again Talon risks losing his ganking power should he be killed as his thirster stacks will be gone and thus he will need to farm again.
Furthering the problem is the power of Akali's Shadow Dance vs Talon's Shadow Assault.
Straight away, Talon's stealth is tied directly to his ultimate, thus he does not have the option of using it to escape if he used it to initiate, he also needs to think about his positioning to achieve the maximum damage from Shadow Assault, as if he positions even slightly poorly, he will miss half, if not all of the blade spread. All Akali needs to do is click on a target and press R.
Akali's ultimate also has a very quick stack refresh when compared to Talon's ultimate, sure Akali needs all stacks to be at her most effective, however Akali also gets stacks back on kills and assists which she will be getting, coupled with mark of the assassin, akali's shroud and her sustain Akali can fight for a much more sustained amount of time for a champion intended to be burst related, Talon has to keep entering and leaving the fight as he simply does not have enough sustain nor way of remaining in the combat area without being in danger of being focused quickly.
Sure Akali's shroud is countered by an oracles, as is Talons Shadow Assault, however it does little to change the fact that Akali is a burst champ primarly with all sorts of extras that make her quite sustained in drawn out fights given the right conditions.
If Talon cannot use his Shadow Assault effectively, he loses a large component of his burst and his only method of escaping outside of summoner spells.
Take what you will from what I wrote there, but I can honestly tell you, Akali is not fine like some would have you believe, if anything she is an absolute prime candidate for a rework as I don't see Riot being able to do any nerf work to her without making her either absolutely useless or removing any kind of fun aspect from her.
Edit: Yes I'm aware how to counter Akali before that one is thrown in, doesn't change the fact that she is broken by design though does it?