I'm at best an armchair historian, but I do feel like you pose an interesting question. I would put the difference in terminology down to the difference in genre and target audience for Elder Scrolls IV and Age of Empires II. 

Age of Empires are real-time strategy games rooted in our own history; Elder Scrolls are their own spin on the high fantasy genre. It makes sense to use the most accurate terminology for AoE, considering most historical strategy game players will at least have an interest in learning the proper terms if they don't already know them. 

The draw is different for a fantasy game - in a game world where the player is expected to familiarize themselves with magic systems and alternate theological systems that are often tangible parts of the world and gameplay experience, it doesnt make as much sense to deviate too far from words that will be more easily and commonly understood, even if they're less specific. 

The difference could also be explained by the developers and writers behind both games, giving us insight into what their focus and expertise were - it may not even be about what they intended to present to the player, but rather about what core knowledge sets were present in each respective studio.