So, classes have constructive uses. Building, crafting, fighting, getting food. How about one that simply increases morale and provides amusement? Specifically, bard and dancer classes. Bard can use one of several instruments (lyre, fiddle, horn, and drum are my choices) to make music, and if another bard is nearby they may play together, increasing the happiness of your hearthlings further. Dancer is the same way, and male and female ones will dance in harmony together to the music.
Edit: Secondary idea, actual use: When leveled up they give bonuses to speed and attack and such, like the knight does.