Can you give me a big list of open world FPS? I mean, I know of Fallout 3, RAGE, and Stalker, but what else exists? I personally think this genre has only touched the tip of the iceberg.
Fall out 3 is an RPG not a fps.
It's both and stalker would also be an RPG by your reasoning. Anything with a first person perspective and uses weapons can and is classed as an FPS. A game can have more then one genre...I know mind blown right?