What is an “actual file format”? Every file format is a serialisation of some kind of data-model. I'm sure the OpenDocument data-model might be simpler and cleaner in some ways than the Office Open XML one. But for something with the complexity of an office document, you can't escape the fact that every file format is full of assumptions about the application interacting with it. I find the examples in the article from [0] unconvincing, it reminds me of arguments about programming language syntax.

(I do not doubt that the OOXML standard is a mess though.)