But what if a DM is not familiar with it? Wouldn't it be nice to have an option in the DMG on how to use these kind of spells? With examples on how to make them fit want more high magic easy travel use a less restrictive teleport want something more dangerous then one with added risk.
Wouldn't it be nicer not to leave a trap for a novice DM to tear his hair out in frustration, as players skip over everything that they can, and his relatively mundane world that he built be torn to shreds of implausibility by having the ability to break time and space?
At least if you hold it off to 16th or 18th level, the campaign is nearly over, so you don't have to deal with all the problems of teleport for half the game.