Well, we need to be careful that players don't be come trapped. If they teleport into a closed off portion of the dungeon, and then don't have a spell to get out, they would have to wander around until they found a monster group and then let the monsters kill them.
As for life after level 10, we have been thinking about what might be done for the really advanced players. We would need to have monsters that would require new strategies, and new rewards as well. If you have any thoughts on the matter, we would love to hear them.