My latest whacky idea . . . we know turbine has the tech to max those little XP gems we get from daily dice rolls.
Why not sell "empty" ones that we can fill with XP by earning XP in quests? Say they can hold up to 1.5 million XP, you run quests and instead of the XP being applied to you character it gets put in the crystal to be used later.
Why would we want to do this? That's easy, ED leveling sucks. These crystals would let you run quests in strong EDs and then later apply the XP to weak EDs . . . would let you play strong while never having to flush XP down the toilet.
Make them BTC or course to prevent exploitation, probably exclusive as well.