Originally Posted by
Lokasenna
The Lord of the Rings was composed over a period of 12 years, and is clearly an intellectual whole. Dante's Divina Comedia was composed over a period of 13 years, and again its seperate parts make an intellectical whole. Wagner's Ring, in my opinion the greatest single work of artistic output our species has ever produced, was composed over a period of 26 years, and yet makes an intellectual whole as well.
This isn't to say that it is necessary for great literature to be meticulously planned in advance - Dickens, for example, never planned much beyond the next chapter, never mind the whole book. I'm just challenging your view that detailed forward planning is that unusual.