While instanced loot is impossible in the current game architecture, a roll system wouldn't necessarily be that hard. But it's still a decent amount of work done basically because you have crappy friends. Also, depending on who hosts the game, it might not do much at all. If you're the host, just open the game in single player and distribute loot in a more fair way. If your crappy friend is the host, then they'll probably just open up the game in single player and take what they want anyway.
And a roll system just makes a tiny dent in the effect of selfishness, and far from eliminates it. Your friends could still roll for items they don't need. And it might even lead to situations where you find something on a hard to find chest perfect for your character, but then your friends roll for it and take it from you, so it could end up screwing you in certain situations.
As the game progresses, and items gain requirements, this will help the problem. Will your friends really be that much of jerks that they'll take items that they literally can't even use but you could just to sell them?
I do think it could be nice to have items compare to everyone's equipped items on the chest screen so you don't have to check everyone's inventory to see if what they have is worse or better.
