This was an interesting article but it doesn't really provide solutions. I watched a few tech talks teaching a new API. Most slides were split, left side bullet poitns, right side either code or an image. As I was watching I was thinking "isn't this supposed to be almost the worst style"? but I was also thinking "I can't think of any way to do this better". It's an API. It requires examples. And it requires something describing what to concentrate on, what the example or image is showing.
I've been the plenty of great talks with just images, no words. But they fit the type of talk. I'm not sure an API talk would be better without bullet points. If you know of some to reference, please post links.
Tufte did make specific recommendations that one should prepare a real document that your audience can and should read, and that they would have in front of them during the meeting. I'm not sure how best to translate that to your API example.
What would make the most important point of that slide stand out any more in a "real document" than in a slideshow? If anything, I would expect it to be buried even more - a slide and limited-time presentation forces you to be concise, while in a document there tend to be few limits on length.
I would say the disaster occurred despite PowerPoint, not because of it. It's not clear to me at all why the slide author thought all that text was needed, when it seems to communicate almost nothing. If anything I would blame it on the culture around "real documents", where having more information is treated as better (probably because they serve multiple functions - to educate, but also as a record of activities), even if it makes it bloated and hard to read.
A document generally has an abstract at the front and/or a conclusion at the back where the important information goes.
A presentation accompanied by a document can be more easily done with punchy slides because the detail is in the document.