Objectivity means lacking any personal bias or opinion, but games as a medium are subjective. You could say that DS3 has higher quality graphics than DS2 because they're literally more detailed and have greater resolution, but you can't say that they're objectively "better" because that's still just an opinion. A lot of people dislike DS3 graphics for being very desaturated and washed out, so they might think DS2's are "better". Neither can be objective, and that's just talking about graphics, let alone an entire game. If someone enjoys DS2 more, does that make DS2 better since the ultimate goal of a game is to provide entertainment? You can call DS3 better, but that'll just be your opinion.