This is true for a few reasons.
1) Any word overuse is a problem. In a medium comprised of words, overuse suggests a limited lexicon and a dull imagination. The reader catches the stale whiff of laziness. Be cognizant of the choices you make.
2) The repeated use of this particular preposition sets up a lulling rhythm. You want to open your readers’ eyes to new thoughts and ideas, not close them. Here is one paragraph from the book I read, with nouns and verbs changed to protect the guilty:
He unbuttoned his coat and tucked his long hair behind his ear as he sat down on the leather couch. The secretary ignored him as she tapped away on the keyboard for another minute until the mailman arrived. He set the mail on her desk as he delivered a weather report. The secretary drummed her fingers on the desk and glanced at her watch as the mailman droned on.Every sentence is bent the same way, hinging on the word “as.” There is a reason lullabies aren’t syncopated. *Yawn.*
3) The reader will suspect—rightfully so— that the author is flailing around for the true conflict that will drive the scene. Flail on your own time. By the time your story reaches print you need to command the material. Publish any sooner and it’s like rambling around outside in your underwear—we’d rather you decide what you are going to wear first! Once you weigh the significance of your story events and order them properly, dole them out one at a time so the reader can sense the significance of each. Due to the complexities and uncertainties of modern life, your reader is already surrounded by impotence: she doesn’t need to invest her time and money to watch it in action. She trusts you to tell your story more effectively.
With most writers this problem lurks in the “stage directions,” as in the “action” above. Since nothing of any import was happening in this scene, the author had the bright idea to make two dull things happen simultaneously! Um—no thanks. How about telling us only the good stuff, one important event after another?
Sometimes the use of the simultaneous construct becomes so rampant the author taps it for major events as well: “As I opened the door I heard a gunshot.” Now, which is more important, the door opening or the gun going off? This is out of context; a case could be made either way. Maybe the character has been trying to pick the lock on that door for weeks. Point being, it is not your reader’s job to know if you don’t.
My money is on the gunshot. If you strip this sentence down to its basic and most important detail, you can even evoke the shocking event with your prose style: “A gun fired.” Such a sentence does not flail. It is confidant, evocative, and on target.
Will using word search to remove all instances of the word “as” solve the problem? Probably not. But it will signal the fact that this type of multi-tasking, conflict-ramping sentence structure is a problem for you. So once you’ve ridded your manuscript of most instances of “as,” search for “while” and “-ing” constructs that attempt to achieve the same thing:
“The secretary drummed her fingers on the desk while the mailman droned on.”
“Drumming her fingers on the desk, the secretary listened to the mailman drone on.”
Think texting and driving, blow-drying and bathing: it’s dangerous to do more than one thing at once. Oh never mind, the results of that kind of multi-tasking could be pretty riveting. In this case, the greatest danger is that “as” you ramp up weak prose by making more than one thing happen at a time, over and over, your baffled and lulled reader will fall asleep.
And your book will fall to the floor, where it is likely to stay.
Kathryn Craft is a developmental editor at Writing-Partner.com. While "astounding multi-tasker" was once a proud bullet point on her resume—and she still serves on two writing organization boards, gives talks on writing, edits, writes women's fiction, and hosts writing retreats—she no longer tries to do all these at once.