In anticipation of its release in two weeks, The Pokémon Company has issued an overview trailer for the upcoming release, Pokémon Bank. It confirms that you can transfer entire boxes immediately within the Poké Transporter system that comes with it and that Pokémon Bank has advanced search filter systems akin to the ones in the boxes on Pokémon X & Y
You can also choose Battle Points to be earned rather than PokéMiles in Pokémon Bank when you deposit Pokémon
If your annual Bank fee ends, you can still withdraw your Pokémon for a short time, but will be lost afterwards forever. The period of time has yet to be announced.
Pokémon Bank ignores the 3DS's region lock so all games can be read and used for depositing/withdrawing Pokémon so if you have a US game, you can put it on a Japanese 3DS with Pokémon Bank installed and put Pokémon on there
battle point mining gonna be much easier xD