The Human Factor
I just wanted to add this ever important piece of Google's puzzle into the mix. Gaining an important top 10 keyword ranking is rumored to guarantee a human review and even if your site is worthy it may not be allowed to hold that ranking. Why not? Because Google wants a mix of result types and you might just have ranked for one they feel is better covered already. In other words you do not fight 10 sites to gain top 10, you fight perhaps 1 or 2 for the given flavor of your articles. Also, algo's only remove malware and adult material from standard searches, humans dole out the penalties.
The above requires human eyes, always will.