Why don't the textures of drywall patches match the room?
Painting with a roller leaves an "orange peel" type texture that you can't match exactly with a brush.  When you brushed your new paint on, the orange peel texture in the unsanded areas just telegraphed through your new brushed paint, but the smoothly sanded parts had no such base texture so they look visibly smoother.

To fix this I'd go over your patches again with a small roller and you should get the same sheen and texture as in the original paint.