That the Points of Light's world is somehow warped by the influence of the inner/outer planes. So, for instance, his version of the Moon Hills have places changed by the Plane of Earth, with portals to that plane and the like.
This is something that is hinted at in 4e as well. According to some Dragon articles, the world was so damaged by the Dawn War that the other planes "bleed" into the mortal world in some regions, warping them and everything within.
Also, his take on the Cloak Wood is that Torog pulled this forest into the Underdark and then pushed it back to the surface, and so the forest was changed by this. That is something Torog did in 4e: he pulled places into the Underdark at whims. For instance, the Underdark sourcebook states Torog pulled a few Bael Turath cities to the Underdark.
So, it's not a change, but highlighting in something that 4e hinted to make the setting feel different than the FR.