New IPs are almost always better than direct sequels, indirect sequels, ports, remakes, spin-offs, or anything else Square Enix might invent. Something about sequels inspires lazy design, like recycled environments, characters, and even plot mechanics. There's something special about a game and a world one has never experienced. Consider Bioshock versus Bioshock 2; the central failing of the latter results from its nature as a sequel.
There is one RPG sequel, however, for which I find it extremely difficult to argue against: Anachronox. This is not an original idea; a sequel – allegedly titled Anachronox Prime – was planned before Eidos cancelled the project. And it shows. Anachronox ends on a cliffhanger, leaving you cripplingly depressed to know that nothing else will come of Sly Boots' deductive and pugilistic skills.
Even if a sequel hadn't been planned, however, Anachronox would be more worthy for one than most RPGs. Yes, the game had atmosphere, funny moments, great characters, a good story, and interesting gameplay mechanics, but what most needs to be carried on is its unpredictable style. I truly believed that anything could happen while playing Anachronox. The imagination inherent in the game is incredibly deep, not only in aesthetics, but in the storytelling as well. Never before has an RPG story seen such wild turns and unbelievably unique deus ex machina.
I would provide examples of Anachronox-style plot progression, but these are best seen unspoiled and not described. Other than the unpredictability, Anachronox brings genuine humor to the medium in a wry style almost never seen before or after in video games. Juxtaposed with comedy, however, are tragedy and poignancy- two elements most developers seem too afraid, or unable, to mix effectively. Anachronox is a game that will have you laughing, smiling, crying, swearing, and cheering, and the best part is that you don't know what you'll be feeling next.
Then again, maybe Anachronox Prime would have done what so many sequels do: rob the parent game of novelty. Maybe Anachronox is all the better because it's the only one.