Oompa- Loompas are little people who come from the jungles of Loompaland, where they lived in tree houses to escape monsters called Snozzwangers and Whangdoodles. They work in Wonka's factory.
There are some very clear problems with this, and Dahl later rewrote them to be creatures from Loompaland and republished the book in 1972. The republished version of Charlie and the Chocolate ...
So there's definitely room for more Willy Wonka stories. We know he's traveled the world, we know he's been back to Loompaland and met Oompa Loompas, so there's plenty of meat on the bone to explore.