@Fulhamish - Surely your 3rd case is, in itself, racist? Why should a phrase be off limits to one race and not another if we live in a society that preceaches equality.
@Manaic - I actually read it, do I get a prize?
---
Having thought about it a bit more, and read some justifications for the changes, I have to say I agree with them. The book is on a number of banned lists because of the language it uses, and changing these words may be enough to remove it from there. At that point it just becomes a case of teaching it correctly.
Just as when studying Classical texts reference is made to the original word, and the slight differences between this and the translation used, so this should be seen as a translation of Finn into modern English.
As an aside, one of my friends is studying Huck for her English degree at the moment. I found this out Thursday night, told her about this, and she went ballistic :P