Well we have to be getting another main game next year, considering they already took the 2 year gap between BW and B2W2, so I doubt they will take another 2 year gap for a main game release already. They usually release 2 - 3 main games before they will have a 2 year gap between a release of one main game and another.
So with that, we should definitely be getting a 3DS main game next year. It's just the question of whether it'll be in June like B2W2, or if it'll be in September like most releases. If its June, we can expect the announcement in Jan/Feb... if its September, then we can expect it in April/May. Either way, it still has a chance of being Gen VI and not RS remakes (although, of course I do hope its RS remakes).