They have already, kind of. The combos done by the Elemental Pledge attacks might have been inspired by the move combos used in the anime.Oh good lord not another stupid idea.
Game Freak will NOT add feature from the Animé at all ever.
Just have what trades are banned stored on the GTS server instead of on the game itself, so they can be changed as the availability the of Pokemon changes.The reason they allow this has actually already happened.
Think back to the days of early DP, the GTS was littered with level 9 and under Dialga and Palkia. Now the simple, not-thougt out answer would be 'Ban any that are under "Level 50 and Under"!'. but see, Game Freak kept the option open, because, low and behold, HGSS had an event that would net you a Lv 1 Dialga, Palkia, or Giratina.
Outright Banning these so-called impossible trades, would make it so people who want to offer up their event can not do so.