There has been rumors about the "next Pokemon" game having another region since Gold and Silver came out. So this is nothing new, although I doubt it'll happen at all. Nintendo is a company, companies like money. Re-makes = money.
However, I could see a Fire/Water combo type coming. It's not been done, and recent Pokemon games have always had that "odd" type combination for at least one of the new Pokemon. It would also be an interesting design, I bet.
Hard Difficulty option seems like a given seeing as how B2/W2 had it, so I agree on that as well.