If they were to implement a Notorious Roulette, I'd prefer it be from the pool of all lvl 50 duties, but apply a random handicap to your party. They sort of did something like this for ex primal challenges at LV fanfest, although if they do it to duties, I hope it's a lot better thought out.

Such handicaps could include ilvl caps, no cross class skills, healing enmity x2, tank enmity 1/2, No aoe skills, etc.