It probably will not be solved in 2.81.
Development meeting shared workboard for 2.81.
It will be for future releases.
Currently, only meshes can be colored. But there are some workarounds.
You can change Extrude or Bevel Depth setting of a curve to be able to see a colored wireframe for extruded curves.
Empties can be replaced by bones.
Bones can be colored using bones groups colors.