I seem to have lost the center line cross hairs in Illustrator CS6.
I draw some shapes, then go to outline mode and the center lines are now missing. They used to work. Still have them in CS5.
Here are a couple of images that show what I mean.
Here in 5 you can see the center points in each shape
Here is a similar picture from 6 with the center points missing.
The center points do show up if I put my cursor over the shape.