Tales of Symphonia or Abyss either could have lovely direct sequels. With the same casts .

Let's see....I can't think of anything. Most games that I love already have sequels up the wazoo. Oh, Xenosaga Ep. III's ending definitely requires an Episode IV damnit.

Edit: I've never beat Vagrant Story, but I've heard it calls for a sequel big time. I don't want to hog all the sequel love for myself, so whatever I'll say Vagrant Story for that fanbase.