Been thinking about this and worried they will go down the route of trying to connect it to Billy's ancestors.
IIRC, the Predator novel explores Billy's tracking abilities and alludes to the fact that he's actually psychic and can speak to his ancestors, doesn't it?
The setting of the film has massive potential, IMO - but Pred against Sioux won't work from a purely tech perspective. If it can easily wipe out hordes of mercs with high-end, modern tech; then I struggle to see how it's a fair/just/honourable fight. Sure the native Americans were expert trackers and you have the "mystic" element to their backstory too, but Preds can dodge Dutch's teams deforestation attempt and Harrigan's sawn off from point blank range. So I can't see how it'll work well enough to carry the torch.