I think it would actually be fun if we get like a “Slot machine” at the beginning of the dungeon where you would it give you 1 challenge, 1 handicap and 1 bonus reward. Something like: “No deaths” as the Challenge combined with “Curse (half HP & MP)” as the Handicap and “+50 Tomes” as the (additional) bonus.
They could even make it so that every party member would get a different set of Challenges, and Handicaps, but the Bonus would only be given when everyone’s challenge has been completed. That way players would be more inclined to talk to each other to verify which challenges and/or handicaps they would have.