It would be interesting to think about how this fits into a plan to advance MediaWiki and other large FOSS projects guided by the Foundation into higher levels of the w:OpenSource Maturity Model. Today I don't know that MediaWiki even qualifies for the "basic level" of that model.
Fitting into a larger FOSS software maturity model
Yes. Thanks for bringing this up. I have been reading about that and thinking about it a bit. There are a number of Open Source Maturity Models -- https://en.wikipedia.org/wiki/Open-source_software_assessment_methodologies, which we can and should draw from to inform a maturity model and strategy for Mediawiki/Wikimedia technical documentation.
In the end, I think the exercise of creating any sort of maturity model or strategy is really about deciding what approaches to technical documentation and communication resonate with and serve our community's needs and striving to get to that place.