Now I hate refer to borderlands again, but, I found the options to trade and duel very small but good features. Me and my friends keep getting loot that
one of the others want, but no way to trade them. We're also debating who could win in a fight alot, most of the time it's like "My golden gun could shred your warlock apart!" I think both of these features would really capture that MMO aspect of the game and would be extremely convienant for those times you need it.