I agree with the OP on this, something has to be done to the leash system. I wouldn't have a problem with the enemies having a long time before they lose interest like FFXI, then teleporting back.
On a related note we need items/abl/spells for a sneak and invisible asap. Exploring some of the higher level areas is near impossible when you have to go through a small crevice filled with level 90 enemies. It's really annoying for someone just trying to collect all the camps and gates.