A 13 paragraph article, ostensibly about Mishra's Workshop, but Mental Misstep was mentioned 33 times in the body compared to just 15 mentions of Workshop. It was really an article about Misstep, despite the title.
Well it's an opinion piece with a misleading title featuring Mishra's Workshop just to get the discussion going.
The thesis of the article is that restricting Misstep will open up more strategic diversity. I have to say that I'm skeptical of that. It's true that Misstep is good against DRS and Dark Ritual, etc. But, empirically speaking, I doubt that restricting Misstep would compositionally change the Vintage metagame, in the short or long term, in any measurable way.
I disagree. 1 Misstep will change the way people approach deck building fundamentally. The rate at which this happens is very much up for debate given peoples recalcitrance to change, and the dearth of deck builders.
But if you could prove a compositional shift that results because of Misstep, I would be more inclined to your view. But that would take more work than you've put in here. I think that the metagame shifts have occurred for deeper structural reasons unrelated to Misstep.
The rhetorical reference to previous, more diverse Vintage metagames, such as the 2013 metagame, is not persuasive, and undermines the article's thesis. After all, Misstep was unrestricted in 2013, and, that demonstrates that metagames are a product of structural forces, not simply extant tactics.
I don't have the time likely required needed to meet your burden of proof, I admit that much. But as for what makes a Vintage metagame, I think it's nearly impossible to untangle given imperfect actors, and the difference between paper and MTGO (technically, aesthetically and financially). It's also an imperfect comparison between now and 2011,12,13 simply because there was no MTGO Vintage (December 2013?). So why even try, I'm just pointing out some general trends and that cards in a vacuum don't create stagnation.