What's the point? You don't get drops that aren't relevant to your class. Loot is instanced, everybody's is seperate. Loot in Phantasy Star Online was shared. Everybody saw the same drops, and if somebody picked up an item that was great for you but useless to them, tough shit, meseta or gtfo.
Trading in a game like Destiny would just ruin the game. So your friend gives you some high level shit, then what? That raid you needed to complete to get the high level shit, it's no longer necessary. Why even buy the game in that case? To look cool in PvP? You spent $60 on something you didn't even want to play. It's so backwards.
Doesn't the game also have some kind of crafting system? Or at least you're required to pay for items with rare materials. You could send and trade raw materials with friends.
The best gear would be bind-on-pickup or bind-on-equip. Your friends would not be able to send you Epic or Legendary items, but they could definitely help give you a leg up or treat you to a hand-me-down assault rifle with some interesting bonuses.
For a game that is supposed to be social, it's vexing how severely limited social interactions are. Can't talk to anyone that isn't in your party, can't trade or sell items, can't give stuff to friends....is "/dance" the only interaction they decided to take from WoW?