Where to write? Where to look?
In discussions with engineers, many discussed a dislike in reading and writing docs. This is a common sentiment in the tech industry and likely in other industries too. For this reason, I suggest allowing people to write where they are most comfortable on the basis that it can be brought into a consolidated search appliance. See Consolidated Search for more information.
Search
Search is one of the most important features of a documentation system. Many documentation systems surprisingly lack a proper search. As people write documentation in a variety of places, it becomes important to look at a consolidated search appliance like Swiftype Enterprise Search or Google Cloud Search. The cost of this service will be far outweighed by a central location that weights results based on the role of the person. This means you can write anywhere you feel is appropriate, further encouraging a documentation culture.
Good documentation
Good documentation is hard. Information, however, is crucial to any organization to disseminate information efficiently. However, an approach where documentation is written in large quantities and published to any platform does not lend itself well to a proper information hierarchy or any sort of knowledge management. These are important concepts to make sure the documentation you have is useful, reads well, and covers the topics you need to cover.
I recommend hiring, at minimum, a technical writer for engineering documentation to help you maintain the quality and quantity of documentation, as well as the organization of that documentation. If possible, find someone who specializes in Librarian Studies and Information as they have specific training for this sort of thing - they have been trained to run libraries after all! Consider this a tech lead, but for your docs.
Can't I automate this?
You can't automate words, many researchers have tried - we haven't gotten far. You need people working to parse human language. Maybe in a decade we will be at a point this can be partially automated, but until then you need someone managing everything from finding information, tag and label hierarchies, and the grammar of the words themselves.
They would likely manage some or all of the following: