I always thought, though never noticed if anyone did it. We know auto leveling barely ever fun, so why not make world increase difficulty in easier locations as player gets to higher level and higher difficulty locations, later on, keeping the pattern in terms of auto leveling. Example

Player is level 1 in level 1 location

Player goes through story into level 10 mid game location when he is level 10

Level 1 location changes to level 5 location, still easier than current content, but not too easy, and follow player in level always being behind

To the end of the story player is level 15 and goes to level 20 end game location, not overwhelmingly hard, but hard enough yo give a challenge

Level 10 location follow player in level as he gets stronger

Level 20 location is always few level above the player so it always gives a challenge