Modify all linked instances It seems that inherited attributes that can be overridden is needed in Blender for objects considering its complexity. In any event, I thought I read that linked objects only have location and rotations unique to each instance, which would accomplish the same thing for me. But when I change the dimensions of one, the others do not change. I also tried this after having made the two objects reference the same mesh. Is there a way to edit the dimensions of all the linked objects at the same time?
You can select a copy of an object and add a Copy Scale constraint with the original object as a target.

Duplicated objects will have that constraint. To copy this constraint to existing objects, select them, make sure the object with the constraint is active, and press Ctrl + C, then B