Problems is, with no incentives to run it there is no incentive to run it. Mentor roulette has this same issue. The rewards are so absurdly low that even the people who do have it unlocked rarely use it. Why risk getting something long and annoying for a measly 10 tomes?
Personally I think a better option (for Mentor roulette as well) would be to make the rewards dynamic depending on the content. Get LotA, alliance roulette rewards. Get Ravana, trial roulette rewards. Get Doma Castle, leveling roulette rewards, etc.
