As you might remember, I prefer the Middle-earth of the published LotR and Sil;
it's the later transformations I have problems with. The idea of neutrals
is an excellent one, and would fit in with the pantheon of Tolkien's spirits as
originallly conceived (and in my opinion carried over to the LotR). I wonder,
though, how they would fit into Tolkien's later thinking, when he seems to
moved towards having his spirits as corresponding more completely to Christian
angels, which led to difficulties about their apparently having offspring, like
(as you point out)
Goldberry.
