How difficult would it be to implement something to make loot distribution more even between parties? I just came away from a run from depth 10 to 14 with nothing but one star materials for loot, while the other players had multiple valuable drops (Creature Carapaces, Bushy Tails, various flavors of Cores). In a previous game I went in and got four three star drops in a row. Both were unsatisfactory: in the former case I'm feeling left out, and the latter left me feeling bad for the other players.
In the end? I suspect it all evens out. Randomness tends to do that. That doesn't make it any less crappy when it's all going to one player. Off the top of my head, an easy way to do it would be to keep up with who has gotten loot of a given rarity, and enforce a limit so that a player won't get more loot of said rarity until everyone else in the party has gotten a piece of loot with the same rarity. So after I get a three star item, I can't get another one until everyone else in the party has also gotten one. Now, if I get a Hailstone when what I want is a Rocket Sprocket, I would still have to trade another player for it if one happened to drop, but this way no one feels left out at least.
Confirmation bias? I am sure there has been runs where you got most of the valuable loot and someone else is the same position you are now.