Though Akali is a hybrid champion, most of her abilities scale off of her ability power. Yes, adding the extra spell vamp from the second part of Twin Disciplines helps, but the heal you get from it is about 10% at level 1. The damage you do from your harass will only end up healing you about 10-30 hp per spell cast which can be unreliable (especially if you're getting zoned pretty badly). The only way to achieve both passives at level 1 is substituting this for your magic pen runes, which helps to tear your opponents up mid-late game. And besides, by using this guide, you're likely get your second passive the first time you b by buying the pickaxe (bilgewater cutlass if you've farmed up enough).

In the end, it's just personal preference. I prefer to have a harder nuke later game.

Good guide, but I'm wondering:

In the guide you're talking about how it's not worth getting your double passive at level 1 cause you like to grab boots and 3 health pots, so why not make sure you get the double passive bonus from runes/masteries alone so you can start with boots/3 pots AND your double passive?