If you have 16 dex, mage armor, and a ring of protection, then you have 17 AC.
If you have 16 dex, mage armor, a ring of protection, and barkskin, then you have 17 AC. Barkskin does nothing.
Overall it's a pretty poor spell. Though unlike mage armor, you can cast it on someone else. Like your 8 dex paladin who lost his armor and shield.
ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHyjrdGkqqShnmKwra3Rop2im5GptrC6jW1ucnBlZnw%3D