Well this build is quite obviously ****. An otherwise good build soured by the fact that the writer doesn't know what magic pen is.

Since this is a mid guide I'll treat it as such and go down from top to bottom to insert recommendations here and there.

Runes:
Quints are fine, yellows: wouldn't it be better to have hp/lvl since you usually won't be faced off against heavy ad mids? Reds: I've never tried flat ap here, but i use magic pen. because it deals with mids who are stacking mr/lvl. Blue: Since Akali's bread and butter combo requires her ultimate meaning level 6 wouldn't it make more sense to use ap / level to get more of a benefit rather than flat ap runes? Oh, and another reason why i personally wouldn't recommend armor / mr(magic resist) runes is because it can be easily countered by picking up a void staff / last whisper / and black cleaver( which is guaranteed these days for most tops.) Which in turn makes health / level yellows more valuable since there is no tank shred anymore.

Items:
boots + 3 health pots is great. "1st B" Honestly if you have enough for both hex-tech and merc tread by first B then grabbing a need. large rod would be better because it would give you enough of a dmg increase to completely control your lane and others. On first B I get a hex-tech of course because it's amazing with Akali's passive and on 2nd B I'll pick up a large belt if I'm being harassed or a blasting wand if people aren't focusing me. (Something to keep in mind since there's no tank shred: health is godly --> tanks are godly = stack health quick to look "tanky" meaning people will naturally focus you less because they're dumb and stop thinking when you scare them enough because of a large health pool along with the **** tons of dmg you pump out.) Everything else in items are fine except grabbing a vamp scepter then rushing rabad hat I find to be more effective than finishing off hex-tech immediately. Oh, and lich-bane or "*****-bane" can be replaced by void staff if needed if they're stacking mr and zhonya's can be replaced by warmog(hp=godly) / GA depending on if your just being hit by aoe or if you're being focused.
Masterys: Are fine, the minor ones like armor are dependent upon if you're in mid or top etc, and upon your play-style.

Pros / Cons:
Pros are accurate. Cons: her squishy-ness is dependent on what you build on her. Yes, she doesn't have true crowd control but in my opinion a good akali is a crowd control just by your presence :3 "Struggles in 5v5 team-fights" I don't find this to be true, because all you have to do is find your target then out flank your enemy. Which means don't *********** in the open so they know where you're at or else you don't be able to easily jump on your targets, aka your targets will position themselves away from you if you let them know where you are whereas if you know where you are then you can out position them and win the day. Oracles is indeed a weakness, but your job as an assassin is to make sure your enemy team isn't capable of being organized for team fights so if you do your gob correctly the oracles won't matter.

MR and Armor:
your examples of armor and MR are good but they only deal with 1 kind of dmg: armor for ad and MR for AP based attack's, whereas health soaks up both kinds of dmg. Another thing to note is that supports with heals are becoming less and less common because there are better alternatives because of increased CC. Meaning the only source of "healing" you will truly have with you at all times is your own through hex-tech and your passive.

Well this is as much effort as I feel like putting into this, hope it helps or w/e. Oh, and update your passive description because of that one patch that was put in not to long ago that made it active by default.

My 1st Guide I am learning the html codes and what not thanks for your feedback :)

You do realize that Akali's passive changed with the last patch, right? No longer requires minimum requirements.
In your very small farming section, you don't say which abilities you are using. Maybe you messed the HTML up?
No item description? Your guide matches other guides already out there, but with no description of alternatives or of play styles.