A very good article and enjoyable read... Being an SEO I have not stressed as much as many others about the jump in not-provided traffic. Personally I do not see it as a massive problem.
As I have said before, the difficult I foresee comes in getting our clients onboard, for years businesses have had the mentality of 'I want to be No.1 for xx keyword', changing this mindset to be less keyword-focused and more about the content on their site, their USP, and asking the 'why' questions such as why should you rank above your competitors are all things that the average business does not care about so long as they are No.1 when you Google search their targeted keyword.
There are businesses adjusting to this way of thinking and I absolutely believe those that do sooner rather than later will reap the rewards as the old saying goes 'content is king' well all I would say is GREAT content is king.
This cat and mouse game we play with Google is why I love SEO, Google is forcing businesses and SEO's to evolve, not-provided is just the latest refinement to that ideal.
It is the job of an SEo to convince our clients to worry less about their keyword positions (which is of far less importance now with localisation and personalition) and instead focus on providing great content in whichever form.