More random details were provided by the Japanese official website, concerning Pokémon Black 2 & White 2.

• Join Avenue and Fes missions will differ depending from version to another.
• The items sold in the Join Avenue depends on the details from players you connected with, using wireless communication or WiFi.
• The items in the Join Avenue will vary from berries, to completely new items, like one that speeds up hatching of the eggs.
• 100 players can play an Fes mission at one time.
• There are rare items and pass orbs as rewards for these missions.
• Fes missions can be accessed through the Entralink.
• You can play mini-games with the Xtransceiver.
• Once Keldeo is in its Resolution form, it will remain like that, unless it forgets the move Sacred Sword.
• There are as many as 200 medals in the game, which are rewarded after completing a certain challenge in the game.
• You can use these medals to decorate your Trainer Card, and a certain amount of them will reward you with a certain title.
• Reflecting Mirror has the ability to change the form of the three genies in both directions. If it is held by a genie which was caught in Dream Radar, it is reversed back to its Incarnation form. If it is held by a genie, which was caught in Black or White, it changes to is Sacred Beast Form. Their abilities will also change accordingly.
• The Piplup distributed through WiFi will have the following details:
  -Piplup (Lv 15)
  -Held Item: Metronome
  ~Peck
  ~Featherdance
  ~Sing

Medals = Achievements. Achievements means more reasons to play all the time. Keldeo staying in its form is convenient, but changing it back, which I may never do, would be annoying if I wanted to constantly switch. And those minigames sure do sound interesting, I wish I knew more people.