I highly doubt that any new Pokemon will be introduced this gen; it's way too early to introduce new Pokemon that can be used in the main games at this point (and no, Keldeo, Meloetta and Genesect don't count because we already knew about them before the original B/W got released).
It's already confirmed that B2/W2 will be taking place in Unova 2 years after the original B/W's events, so I also doubt that there will be a new region or if you get to explore the older regions.