Keeping your audience in mind is obviously a big deal when it comes to writing. People argue over how or when to be thinking about them, whether you write for them or yourself, whether a large or narrow audience is better, or whether your audience matters more when drafting or when editing- but one thing is clear: audience matters. If it didn't we wouldn't spend so much time debating it.
It is my personal opinion that keeping your audience in mind is more important when editing and reviewing your paper. If you want to be drafting with an audience sitting on your shoulder, there's nothing wrong with that, but I don't think anyone can say that it is the way to write better. It seems to me that the process of writing is often hard for writers. Getting something on the page at all is often intimidating, so we should do whatever works best for us to make it easier. If that means blocking all thoughts of an audience out of your head, then do that. If that means writing to a single person or writing to all your primary and secondary audiences, then do that!
For the first part, the drafting, just do what works best for you. Find your rhythm. Know yourself and what makes it easier to write. So many professional, famous, and beautiful writers have different opinions on this because nothing works for everybody. They all write from their own experience and what works for them.
During the revising, though, it probably is best to keep your audience in the forefront of your mind, regardless of if you did from the start or not. In the end, we are writing to someone, and strong writing (in part) means you know that audience and how to write directly to them. To never think about your audience at all is not only just bad writing, it's terrible writing.
But as long as you end up making what you write for your intended audience, it doesn't matter how you get there or when.
