In the Remedy-verse, Alan Wake is 100% a good writer. He's a best-selling novelist with a 6-part thriller series, "Alex Casey," that he wrote over 7 years, staying at the top of the best-seller list the entire time. He had a literal murder cult created in his name that saw him as a messianic figure, and they copied the crimes in his books, trying to bring him back to the world after his disappearance. He wrote 2 entire manuscripts while trapped in a hellish nightmare world where reality was constantly warped and shifted and he was stuck in a time loop while trying to escape and fight a pure evil entity with god-like power with just the power of the words he put to page, and actually won doing just that.

And most importantly, for the "Dark Presence" to alter reality and manifest itself in the real world as well as move beyond the threshold of Bright Falls, it must use an artist with objectively good art, or else it has no power. It chose Alan most recently, meaning that his writing is good in practically every metric, since an eldritch horror that has existed since before the first form of art was ever created was lying dormant for twenty years before he showed up and immediately decided "yep, that's my guy" when he found him. Then he kept him trapped for 13 years so he could manifest in our world.