Todd mentioned that shift+parent has some new functionality in the "What's New" post.
(http://blogs.adobe.com/aftereffects/2013/04/whats-new-changed-after-ef fects-next.html - See "changes to Shift+parenting behavior:")
However, I've noticed another change that is less than desirable. When shift+parenting, the child layer jumps to the comp center coordinates (eg. [960, 540]) instead of the anchor point coordinates of the parent as it would in CS6.
Is this intended and/or should I report a bug?
I think you are misinterpreting what it says in the explanation. Let's say your child layer is at 200, 200 and the parent layer is at 400, 400. If you hold down the shift key and select the parent layer the child layer will move to 400, 400 in the comp window. This happens whether or not the child layer was previously connected to the same or a different parent layer.
After holding down the shift key and selecting a parent the position of both layers should be the same. The position values may not be the same, but the actual position should be. In other words if you child layer and your parent layer were both 200 pixels square they should overlap perfectly when using the shift + select parent feature as long as the anchor points for both layers are the same are the same.
That's what I'd like to happen and has happened reliably in the past. As described in the OP, it does this by using the parent's anchor point coordinates as the new position coordinates. That is, if you shift parent to an unmodified null, the child's position property should always become [0,0] and it's anchor point should be at comp center. This is not the behavior I get when the child already has a parent.