Deathdrop,
Yautja,
10 years ago
Here's the thing: Are we talking a new Predator movie, or a new PredatorS movie? Because to me, a Predators sequel would have to explore more of the planet and show us some stuff we haven't seen before. New extraterrestrial monsters/animals, new environmental hazards, new parts of the planet, more of the classic vs. beserker feud... It would have to build on the first movie, in other words, probably using the same characters. Personally, I think expanding THAT story would be better left to the comics, where there's no budget, and they can REALLY go all out with exploring the place, flashbacks, etc.
As far as actually making a straight-up predator "reboot," I think the best thing to do would be to go back to one Pred hunting a group of badasses, though that runs the risk of repeating what we've seen before, so maybe mix it up by playing up the conspiracy angle? ie: The governments of the world know about the Preds, know they've been coming to Earth for thousands of years (at least), and cover it up because they also know there's nothing they can really do about it.
I think doing a period piece could be cool. Maybe even have it in two different eras and cut between the two to tell a longer story? There was a DH comic called "Bloody Sands of Time" that did this really well. I've always wanted to see a sort of black market for Predator tech develop, so that's one thing they could try.