I agree. Currently if we need to assembly a centered part we have to previously create a centered plane both in the source part and in the assembly. Sometimes we don't want to modify the source part, only to add a centering plane for assembly. One workaround is to assemble using offset from one of the faces, and tweak the offset value to guarantee symmetry. Which is not the best way, when sometimes the parts can be modified, and the offset value would have to be tweaked again, but having no error in assembly regeneration, it means that it would be unlikely that the offset value would be changed. Most parts are assembled with tolerances, so, rarely in an assembly we should assemble with coincident constraints, the offset is related to the tolerance. But when assemblying symetric parts, which could be imported, or not having already planes in the middle of the part, it should be possible to select two pairs of planar faces, one in the assembled part, and one pair in the assembly, and Creo automatically center the part as if it was creating an internal middle plane in the source part and one in the assembly, and aligning those virtual middle planes.
