They should go one step farther and take a look at the self-mentoring system from EQII. You can go to an NPC to set yourself at a given level ending in 0 or 5. It's really nice there since quests "grey out" and no longer give experience. You can mentor down so you can do them at a level that gains experience or alternate advancement points. Or you can mentor someone in a party to go to their set level.

CoX had the option to mentor partymates, too. It's very nice in MMOs.