Basic problem is that even after you have progressed in terms of weapons, armor, and skills, you sometimes you want to go back to Haven to either meet a friend, greet new players, check the bazaar, etc., really, any number of reasons.
If someone who spends their time at the deeper levels wants to go to Haven they must accept that they'll have to work back down to Emberlight, 18 levels deep. The problem is that this is kind of boring and grindy. Often these are the same levels you can play when you are deeper except the monsters are neutered, as is the treasure.
This can end up creating a big problem of de facto segregation of new and veteran players, as new players will tend to be up higher, and veterans will congregate deeper, and rarely go back up higher, and the middle safe places will probably be ghost towns.
I'd like to see the disincentive to go back up the clockworks greatly reduced. For seasoned explorers (however you determine that), there should be shortcut levels available that are longer than normal levels, and much harder. So if I go back to Haven, I'd be able to take a long, hard shortcut level back to Mooncroft, then another long, hard shortcut back to Emberlight. This would hopefully be fun, instead of the time sink that traveling down 18 easy levels currently is.
I'd also like to see something like this.
Also there's the energy factor of having to spend about 160 Energy if you want to go back to Emberlight.
Unless you have a friend with plenty of energy and good will to let you join him in dungeons just before reaching towns.