Be nice to have a way to gift expansions (or weapons/armor) to other players. Set it up to be able to buy the expansion, via in game, then gift to other player in game. How about the option to show the person that gave the gift, or not. Make it an Ultimate Engram. Make it a special prompt for the receiver. And maybe they go to Tess in Tower to unlock it. Be great incentive for clans. They can have personal contest on PVE OR PVP that if they win (tournament or what have you) there is actually a prize.