Are you sure?
Just I'm sitting here right now and in the Scene View I can adjust my objects (sprites) position using the transforms->Position->X and my object moves left and right on the scene. I also within playmaker set the X position to -10 or 10 to determine if the object will start from the left or right side of the screen.
To me, in 2D. X is left and right, Y is up and down and Z is Depth (Well drawing order in 2D).....
I'm only using the 2D collider to determine what object hit, after that its the standard Get Position action....
very Confused now.