Architecture should reflect a land in decay, with Roman cities depopulated and being overgrown with weeds. The people should be shown as vital, alive, and historical. This includes brutality and humor, life and death alike. Saxons are proud because they are still populating Britain. Picts are defiant in their distant lands.
People have dirty, tattered clothes.
Lands, times and styles should revert to post-Roman Britain and the Dark Ages. Art covering adventures in the wild should be even more Celtic and Dark Ages in their influence. More emphasis should be placed upon animals, vegetation, water and landscapes, atmospherics, sky and heavens. The natural landscape itself should have heroic, romantic qualities. It should make you want to subscribe to National Geographic or personally venture into the wilds.