3. Most Anime
Almost every successfully popular Anime series has been praised for their merits in managing to create large, complex worlds with interesting characters and environmental traits such as magic and alchemy which all combine to make a viable pitch for any number of open world games. The distinct stylistic features would work well if implemented in a Borderlands-y cartoonish tone, and character building menu's would be simple to incorporate. The variety of Anime available for transfer to an open world format, which has already proved lucrative from the Pokemon range, is enough to keep a narrative going through any storyline. If they were even to enhance the Pokemon format to a graphically improved, 3rd person adventure game, I'm sure that would be enough to keep people playing.