I'd heard about these banned illustrations, but hadn't seen them until I came across this old Japanese publication of the book, thought it might be interesting to others as well.
The evolution of this children's book in relation to society implores further consideration in many ways, including this one. Personally, I'm very impressed with how Tim Burton kept this original concept in tact while avoiding an immediate comparison to African-American slaves (the singing and crates being especially provocative in that regard).
The first movie, Willy Wonka and the Chocolate Facatory, used the infamous orange/white/green complexions to deliberately avoid potential accusations/objections of racism. Later publications changed the appearance of the workers to be extremely Northern European looking, resembling closer the idea of fairies, Leprechauns or elves. At this point, I'd say they've become a melange of all these concepts but their origin is indicative of history and therefore shouldn't be forgotten.