Network problems have caused many interruptions for gamers. Users have had a hard time getting new games, even a free title on Steam, and had to wait many hours for Steam and the PlayStation Network to return to normal. Every Thursday, we expect new games via Nintendo Network but the huge traffic on the service has caused the postponement of new games and apps, including the launch of Pokémon Bank & Poké Transporter.
According to Nintendo via a post published today on its support page:
Nintendo and The Pokémon Company International have postponed the launch of Pokémon Bank and Poké Transporter – two software applications that were originally scheduled to launch for Nintendo 3DS on Dec. 27 – due to a large volume of traffic to the Nintendo Network service. Due to the high traffic, players are having trouble setting up Nintendo Network IDs and downloading content in the Nintendo eShop on both Wii U and Nintendo 3DS. We truly regret the inconvenience, and wish to reassure everyone that providing a solution is our top priority. We apologize for the delay and thank you for your continued patience.
No new date has been announced yet. Pokémon Bank & Poké Transporter were briefly available in Japan.
[Source]: Nintendo: Pokémon Bank Announcement [http://en-americas-support.nintendo.com/app/answers/detail/a_id/2393/p/430].