The author has lots of good points. Because I write most of my Python in the style he is advising against, I recognize that style has issues. The main issue for me is that a dict of dicts of dicts is not an interface. It doesn't have any constraints. It doesn't communicate expectations for use for the actual intent of the code. The best you can do is a comment explaining what to expect and a lot of error checking.

That said, almost all of the python I write these days is in the form of functional transforms on built-in data structures. And I love it!

There was a great Pycon2012 talk titled "Stop Writing Classes". You can find it linked and discussed here https://news.ycombinator.com/item?id=3717715