The Mentor roulette Reward should have 3000 commendations as well bound to it, too many mentors just spam mentor roulette, and giving a damn about the group, other than their own ambition to eventually get a mount, make it backwards compatible, so those who already did x amount of mentor roulettes or enough, will not be able to summon that mount, before reaching the criteria.

As for Trade mentor, even 3000 collectables would be an easy task, as it can be done on auto pilot, make it so you can't macro any collectable solution and it has to be done by hand.