For special treasures like Dungeon and Quest Treasures I would like to propose altered loot tables based on how many player characters that are present.
More players= more gold and more loot (max cap at 8?)
** We shouldn't change the map treasures at all, as this would encourage people to hoard their maps and only hunt in groups of 8, making maps far too easy and the reward too good. **
This lets smaller groups that can surpass the challenge still get rewarded, however this would ensure that it is still beneficial to go in a large group!