the duty roulette is a feature added to help players whom do not have access to full group by enticing players with rewards for helping them out - and by helping out, that means you dont get to choose what YOU want to do since you are helping someone else out with what THEY need to do...and if there is no one in need at the time, then players are given RANDOM duties by the game - if players want SPECIFIC duties, all they need do is select the SPECIFIC duty they wish instead of using the RANDOM feature...