For a party balance, archetype doesn't define it. A house can be built out of dirt, stone, metal, wood, bone, glass, plastic, and etc. Archetype is basically the primary material to build a character.

All of the actions that characters perform are from skills, spells, and maneuvers. All archetypes have access to all skills. It is just that certain archetypes have an easier time excelling in certain skills. Party balance is more oriented to having the more specialized skills covered or compensated.