I've changed this build quite a bit. I no longer use Heal because, well, I like Ignite while using my Ultimate, and, I DO still take Clarity, but sometimes I go with Teleport. I've been awake for 36 hours straight right now, but I DO plan on updating this. I still play Malzahar quite a lot. And since I play him so much, I'll probably continue finding new things I hadn't though of.

The DFG rarely makes my final cut now too, because I REALLY like some of the other items I didn't get a chance to talk about on here, but I think some of the ones listed may have been talked about in the section where I mentioned that I don't stick to one set of Items. Malzahar should be played in a variety of ways, because he's so much fun.

Anyway, the Armor Pen, is most likely a mistake, I don't use that with him either.

Personally, I do not think that Heal and Clarity are necessary for Malzahar. He needs some kind of escape method such as Ghost or Flash. Clarity doesn't seem to be a necessity for this build because Archangel Staff, Nashors Tooth, and Deathfire Grasp already gives a total of 50 Mana per 5 seconds.
and the 2 points in offense for armor penetration is useless for Malzahar.