The reason(I believe) that Lovecraft had the writing style that he did was that it fit his type of story. Most of the main characters were scientists or highly educated men, and the stories were written as documentation of the events that happened to these men. Therefore, they wrote in a convoluted style that befitted their place on the social and educational scale of the time. Remember, a scholar would want to make his works look excellent. Also the gothic touches of color in HPL's works wouldn't
work if it were written any other way. He might mot have been the best, but he towers above the majority (my opinion)
