Can someone confirm my experience with this? It seems that in a party, more crowns drop, but the SAME amount of items drop. So teaming up in a party is good for your wallet but bad if you want items; it's much better to solo for crafting ingredients, it seems.
I do not believe more crowns drop when in a party, instead the crowns you earn are multiplied so everyone gets the same amount. So, if a level yields 2,000 crowns when you play solo two players will get 2,000 crowns apiece.
For items, Tokens are shared evenly with the party (each time a token is found all players in the party get one) and those can be exchanged for rare ingredients. As a bonus, if you have a group you can more easily withstand danger rooms and arena levels which results in an increased amount of loot to share on top of added chances for more tokens.
I think the balance between solo and party is pretty much where it needs to be.