I would define an RPG as a game that allows me to curate my playable in a significant way, with both choices of playstyle (stealth, magic, slow combat, fast combat, etc.) and narrative decisions. I know that on paper Horizon has both of these qualities, but I'm not yet sold on how big of a role they will play in the game. These days almost every AAA open world game has lite RPG elements. Assassin's Creed, Far Cry, the Arkham series, Watch Dogs, hell even DOOM have upgrade points and skill trees, so hearing that Horizon has three skill trees doesn't convince me so much that it's an RPG as it does that it's a modern AAA game. Until I see how intricate Horizon's skill trees are I'm going to assume that I can put points into say, shooting, stealth, and gadgets and will have enough points to get the must haves in all categories. As for the narrative decisions that could impact the story, Guerilla has said that this is only a few things and the impacts are small, so I'm not expecting The Witcher in this regard.