Why would you choose to make something difficult to use? Are you deliberately putting barriers in the road? Or are you just forgetting the main reason why people pick up a document or manual?
Long ago, when I had just started out as a technical writer, I attended a course on designing for Print. It covered many things, from typography to layout and I still use some of the basic design rules I learned way back then.
Whitespace, choice of font, and hierarchical indentation can help make a document more readable. Clearly delineating the structure of a document without explicitly stating it as such, leaving visual clues to help the reader navigate the page (presuming you’ve covered the multiple navigation routes they’ll take to get to that page of information).
Such considerations will continue to become more important as more and more information is moved online, and is then available in a variety of media formats and devices. Structuring your content, and using visual clues to convey that structure clearly, will become ever more important.
At this point there starts to become an obvious overlap with usability, pushing technical writers to start thinking more in terms of the user experience than simple task analysis allows. Understanding the reasoning behind a user action will become equally important, and can be passed to development to influence the UI as well as directly impacting on how we present technical information in the future.
Beyond that I’m not sure where else this may take us but I do know that part of the reason I love this job is the cross-over we have with so many other professions/industries, and I can’t wait to see what is next over the horizon.