You can now assign different colors to curves and surfaces (both active and inactive) through Preferences > Interface > User Colors.
We replaced the Model color with separate sliders called Curve and Surface.
You can also assign different colors to mesh and mesh cross sections (both active and inactive) through the Mesh and Mesh Section sliders.
Miscellaneous items that previously used the Model colors (active and inactive) now use the new System colors (active and inactive). These include: