Kettle, met pot, pot meet kettle
A fundamental requirement for a specification to be open is to have more than one interoperable implementation.
Both of these are guilty as charged here. There is _NO_ interoperable implementation capable of catering for the minimal set of features required in a templated structured document. These do not ineroperate between themselves either - I will believe them to be interoperable on the day when libreoffice will successfully read-in a DOCX index and bilbiography and vice versa. That is still a decade ahead as it was a decade ago.
In any case, on pot-kettle/kettle-pot. With the practical demise of KDE and Koffice there is no second implementation for ODF anyway so it fails to be an open standard. Same as MSFT. None of them is and none of them will be until there is one.
Lesson for both of them. If you want to establish a standard _BUILD_ a second interoperable implementation. Slap a GPL2 (if not 3) on it for good measure so it is usable as a reference implementation but cannot be commercialized in a way which is adverse to you. And be done with it. Yes, I know, this trivial idea is a bit too difficult for people who have drank too much of Redmond water supply.