I have not been able to read all the messages here, but what I do not se much of is a discussion about business models.
People come here with a problem about traffic dropping and people try to help by asking technical questions about the website in question.
I often wonder what is the business model of the site that dropped. Because Google appears to be grading business models. Example. I have a prospective client who wants me to fix his traffic loss. He has 20 domains each one for each brand. No real info on any of his sites and he is selling some information on each brand. I can see some value to his service but I am sure Google considers it a spam service. 20 sites all the same linked selling the same product.
No amount of tweaking to this site or that site is going to fix his problem in my opinion.
I wonder how many others are like him?