I find that originality and a sense of mystery are instrumental in elevating a cRPG to true greatness. I realize PS:T catches some flak around the Codex because it's an oft-referred-to darling of the unwashed masses, but even so, few would question its originality and sense of mystery—in terms of TNO's true nature, the relationships with his various companions and acquaintances (and enemies), and the interesting way in which the already fairly exotic Planescape multiverse is utilized. The first-time player had no idea what to expect from any location or character, even if they happened to be familiar with the Planescape campaign setting prior to 1999. Of course, it's vital that the mysteries are enjoyable to uncover, which is where good writing and characterization come in.
Direct sequels are hard-put to achieve the same sense of originality and mystery as their predecessors. So are games utilizing generic fantasy tropes, standard fantasy races, main character(s) without unique background stories, and so on. Project Eternity fails somewhat in the "setting originality" department, appearing (to me) to be rather generic with a few twists and dabs of paint to pretend that it's not, but hopefully that won't hold it back too much.
Give me originality, mystery, good writing and characterization, choice and consequences, and satisfying/meaty/challenging combat/ancillary game mechanics, and I'll open my wallet. Unless the game's not story-based at all, which is fine, but if it isn't it's probably something other than a cRPG.
