Ive been thinking about this leveling thing, and under risk of provoking solwyn, heres my two cents.
I think it'd be good if there were two kinds of areas in all parts of the world. For the sake of legibility and RPG cliche, I will call these areas highways and forrests.
The 'highway' areas being the ones that do not level. If you stick to the paths, towns, and well lit campfires you will encounter a set resistance. rats>wolves>goblins>trolls>giants>badass evildoers etc.
The 'forrest' areas being areas that are scaled to your level.
This way, you notice when you're skipping a bit too far ahead, because the highways are getting difficult to survive getting from A to B, but when youre the famous hero and return home, sure the bully from your adolesence is gonna wet his pants, but there are going to be beasts and assasins waiting for you in the shadows.
I am ingeniotic.