This article is interesting, but in case you're like me and read comments before articles to get a tl;dr, this article is about web design. I was personally hopeful it was about managing teams or projects, which does have analogous lessons, but it's specifically about web design.
Disclaimer: no longer a web designer; take my opinion on the substance of the article lightly.
There is much to add to this list. For instance the task of writing concise copy. It can take a lot of work to get there. A simple form may require only a few sentences to guide someone through but getting everything in a logical order can require several iterations. The finished result may be the result of many, many tests. Sometimes only working with the form and building the backend for it is how to get to the result. In fact you need to know that problem space to get there. The finished results should look effortless and simple but there may be many commits leading to getting there.
I saw a talk on Friday about designing interfaces for people with locked in syndrome. It turned out that to be effective they needed to design for increasing cognitive load rather than reducing it.
As everyone knows, how and when to employ a principle is the key!
I hate that stupid stuff-animates-as-you-scroll crap that's been all over the web in the last few years. If I'm on a web page it's because I think it has information that I might need, not because I want to admire artistic fades and be drip-fed single lines of text.
Disclaimer: no longer a web designer; take my opinion on the substance of the article lightly.