Key word. "Mod" if it isnt part of the original game it isnt what you base your assumption on. If you are also going to use the "you can shoot bows" as an arguement for a fps then by that same logic, we can take Jak and daxter and say because you can ads and shoot yellow eco, is now a fps. Clearly the game is not. A fps is a game that revolves around playing in first person while shootinging things. Skyrim may revolve around the first person point of view but does not revolve around shooting. You can play the entire game and hit almost max level with out evee shooting a bow.