The game's contents haven't really been pushed out to the public yet, apart from the fact that the two main legendary Pokémon, Zekrom and Reshiram, will have new forms, as well as a new Pokémon Masuda affectionately refers to as "Black/White Kyurem". Masuda has left us in the dark about the game's specifics, and as a result we do not know whether the game will be a direct sequel or a modification- a la Pokémon Platinum.
Astute gamers who reckon that The Pokémon Company and Game Freak are running out of colours to choose for new Pokémon games have presumably had their emails left unanswered.
The two games (Pocket Monsters Black 2/ Pocket Monsters White 2) will be released in Japan this June, with a NA region release coming soon. The EU and AUS regions have been left in the dark at the time of posting.