Fiction writing is not a linear process. To understand we have only to look at creativity itself.
Creativity is a subtle and magnificent dance between the rational and the intuitive, between the left and right parts of the brains, between technique and imagination. Both partners in this dance are absolutely necessary and are needed in equal proportion, which means that imagination is not more important than technique and visa versa. If you only live in the imagination, you will never get organized, you will never complete your story. However, if you start from the rational, linear, organizational part of the process, ( ie. Gotta have the perfect opening sentence and first paragraph... better yet, an outline...) you will never fall into the rich, passionate cosmic landscape of the imagination where anything is possible.
However, the main problem I have seen in my thirty years of teaching fiction writing is over-dependence on the rational part of the equation. People want to get the story written and get it out. (Whatever that means?) The want to leap frog the process, get the words down on the page and finish the story. This is to symptomatic of the goal oriented society that we live in, a society that is striving upwards toward success instead of embracing the deeper, more powerful and life changing journey of descent that takes us into the creative realm of the true self.
"The intuitive mind is a sacred gift and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift."