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…
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.
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.