This kinda has bugged me for a while, but I wonder why the interface for the move/copy feature allows translate and then in constraints you can use all your basic constraints you'd find in an assembly but none of the "advanced mates".

I understand why you can't use limit dimension or limit angle as bodies need to be stationary unlike an assembly, but I wish I could at least use the Width and Symmetric Commands as more often than not I would prefer to use those with inserted bodies and instead have to use obnoxious offset dimensions (which don't keep proper relations if I change things in the model) or the more robust option where instead I have to create extra planes that are built using the geometry I'd want for symmetry and then making that coincident.

P.S. I use SolidWorks 2012 so if this is an item that has been added in future releases you can ignore my griping.

~Eric