I would suggest that at about leve 40 or so, players get the option to take a mission that lets them teleport to any zone in the game, excluding, maybe, the Shadow Shard.
As for the shard... I'd suggest more teleporty thingies instead of the gravity wells. They're fun (Especially to watch characters flail as they fall), but impractical Also, REVEAL THE WHOLE FREAKIN' MAP. It's too confusing to navigate blind if you can't go "as the bird flies"