Writing well is a skill that is easily overlooked, but essential for a successful project. This skill applies documenting user stories for software or storyboarding a training video. The goals must be clearly written and communicated so that everyone understands them.
I believe very strongly in the power of the written word to provide clarity. Although the loudest voice that is heard, the clearest voice is followed and remembered.
I have written over five thousand pages of specifications, training materials and support documentation. That is experience worth having on your team.