Yeah the AP on Guinsoo's Rageblade might be a bit too much, but it increases the damage of your ult be quiet a bit. I find it usefull to kill runners ;) Wit's End might be a pretty good idea, have too try it. Infinity Edge on the other hand gives you a nice AD boost, but you wont be reaching the 2,3 (Full stacked Guinsoo's Rageblade) AS with it, i suppose. But also Infinity Edge also going to be tested :) thx.

For onhit kog it is a pretty basic item, since you benefit not only from the passive. The 40% AS is just awesome.

For the AD glyph, I mentioned why i use it in my guide. just try it on your runebook. It will give you 1 AD instead of 0.28 AD. Dont quiet undestand why you think that tier 3 AD runes are useless.


Edit:
The AD Glyph "trick" was called out by chaox from tsm so you can check aswell their youtube channel too find it ;)

Edit 2: Couldn'tfind it on their channel, but here is a video from his stream http://www.youtube.com/watch?v=w20gfrHA3QM . But if you look his stream sometimes, you will notice that this is chaox :)

This is nice.

Madred's Bloodrazor is great for on-hit Kog.

You really don't need that much AP. Try switching the Guinsoo's Rageblade out with an Infinity Edge or Wit's End.

Madred's Bloodrazor is just Useless on Kog'Maw, i mean you only buy it if the enemy team has alot of tanks/offtanks.

Why a AD Glyph? It's Tier 3 Rune, so it's just useless too.

Needs to improve dude.