Trading system
They should add another aspect of trading to the game. Currently I have so many duplicates of cards it's not funny. I think they should introduce trading cards for pack points. I don't mean 1 card for 1 pack point.
Im talking 1 pack for - 4 x 4 diamond, 6 X 3 diamond, 8 x 2 diamond or 10 x 1 diamond. But the player must have 2 copies of whatever Pokemon they traded still left in their collection after the trade. It might encourage more players to keep pulling packs as well as and possibly buying more gold. As they know that when they pull more packs, the cards they don't want can be traded back into the system and increase their chance of pulling the Pokemon they are chasing, as more cards pulled means more cards to trade back in.
Just a thought