pemerton said:When I play a RPG I am not going to experience fear because of the referee's narration. That's a response appropriate to a book or film, perhaps, but not a RPG.
I think your quote bolded by @lowkey13 is quite interesting. I remember some Dungeon articles back in the day provided advice on various methods for GM narration to inspire gothic horror and a sense of unease in the players for horror-themed campaigns. In that sense, I see the importance of form being on par with the content.
@Lanefan touched on this in his post upthread.
Sometimes DMs impose a distinct tone using sentence structure, music and props to evoke a certain mood. In those instances I would say the GM narration is very much a literary endeavour.