Exploring is definately a plus - just going overland on horseback between 2 cities (i.e. offroad) I came across 8 or 9 ruins, caves, forts and shrines. If my brief offroad exploration is any indication, the world is PACKED with content
My only trouble is I am getting used to seeing the night time world / inside of dungeons through the blue filter of Khajiit Night Vision, so I often miss how beautiful it can be...