what's the book's view of the idea that 'black skin' = cursed and/or less valiant in the pre-existence

First, the book is no longer in print, due to "low demand" (riiiiight!).

Secondly, it depends on the edition. He softened and modified over the years.

Thirdly, it says both things.

At this point, the church states that this (less valiant) was never doctrine, in spite of many statements made by church presidents, etc.

This obviously begs the big question: What constitutes church doctrine? What is firm and unchanging? I asked this of a now emeritus 70, who stated "nothing".

So, if you can nail jello to a wall, you can also determine church doctrine.

Whatever they are, they are make believe. Just like all fairy tales.

This is a good example of things that were taught as doctrine to us growing up that are being swept under the rug today. And the children now in the church would call us anti-Mormon, simply for repeating what we ourselves were taught as children.