The combination of a subject matter expert in project management, both traditional/waterfall and agile/scrum, with certification in both.
Experience and success as a developer of training courses in project management, which integrate presentation of content, personal exercises and simulation exercises in which participants work in groups using gaming devices like game-boards, dice, chance-cards, etc; creating a fun environment that fosters learning.
I have courses already developed that could be used as a starting point for your organization.
You cannot go with a content writer that does not understand project management. I do both.