When it comes to knowledge managment the two biggest priorities are pretty obvious:
Knowledge management is firstd about looking up information fast. Any knowledge management system therefore has searchcentricity as its top priority. Whether a user is going to use grep or a search bar on a web interface, these should get the most attention. The ideal interface will autopopulate as the user speaks or types their keywords (such as MkDocs).
A close second in priority is the ability to quickly create and save any knowledge into the system instantaneously. While there is formal, organized content there must also be a way to input quick content through speech interfaces or quickly written notes. In fact, it is this informal content that is the most important to ensure that ideas are captured when they happen and not forgotten. It is particularly important, therefore, to not put too many constraints on the way content is created. Even forcing someone to learn a simplified Markdown language might be too much.