I doubt this is the reason and it is just improvement, but I like to think that as the art style got more detailed and "darker" it was reflecting Erens changing view of the "world" throughout the story.
@IDrop4yu This tier list gives me period cramps and I can't even get period cramps, what do you mean these two are near the bottom in what I presume is "trash"
This list has to be rage bait, and engaging with it any further will only cause more pain