[Galadriel]

I am quite content with his works, but since this is just a dream:

1. I would have liked to know what became of Maglor after Maedhros died.
2. More stories with Tom Bombadil. His episode in LotR seemed so fleeting.
3. A little more elaboration on the lineage of Thranduil. I know Oropher was his father, but other than that I have no clue.
4. I wish Tolkien would specify a little more on hair and eye colour. It was rather irritating to read about characters who were nothing but a blob. Eg: Legolas, Ecthelion, Fingolfin, Frodo, etc.
5. A little more women in the stories. They seem to exist mostly as 'prizes' for the male heroes, even if they are strong.
6. More detail with deaths and other scenes. It seems very rushed when Tolkien says 'and hence he died, fighting a werewolf' etc.

That's all I can think of for now, but maybe I'll post more later...