Writing should be an exercise in direct communication. While many may view this statement as obvious, a lot of writers break this rule. Writers can tend to wander or write several abstract concepts together. Abstract writing is lazy writing. Whether this writing is on purpose or accident, writers need to continue to focus on simplicity.
Most writers want to be read. Building a simple to understand concept, or flow of concepts, makes a piece easier to read. Readers find this easier as each reader is coming from a different background. Some may have had a horrible day right before reading the article or book. Other readers may have had the best day of their life. Appealing to a broad spectrum of readers, by having a simple, focused point, means that reading the article can be consumed regardless of the previous day.
The average person can remember a list of seven or so items in their short-term memory. Making writing deep instead of wide appeals to short-term memory. Comprehensive / Wide writing includes adding a wide range of things to the list, most not relating to each other. Deep writing contains this list to a short number, then expands on each point. Writing deep allows a reader to be into the work, whereas wide writing may leave the reader frustrated with too many things to remember.
Excellent writing is said to be merely fulfilling promises made. All readers are hoping for a good return for their efforts. Delivering promises made throughout the piece gives the reader a sense of fulfillment. A writer should focus heavily on what promises are made and deliver on them to the best of their abilities.
Writers need to focus on their content by understanding mass appeal and promises made. The additional focus a writer pours into this will allow them to write much better content. The better the content, the more the author will be , which is the true purpose of writing.