There really are no set rules for me to create a great rpg. Many of my favorites have been radically different from each other, i.e. Final Fantasy 6, Secret of Mana, Dragon Warrior(s), and even Earthbound.
One thing that is laking today in many games is an interesting cast of characters. Shadow, Locke, Kefka, Chrono, Vivi, Sprite, Alex, Choko~, and many others aren't hugely different from most bad characters, its just that they some how shine through from either a staring role or to main character status. There really hasn't been a character that I can recall recently that has been a total package: cool design, unique history, well defined or suitably mysterious personaility, useful abilities, and the intangible x factor that makes a character complete.
FF6 managed to do this better than any other. Of all the cast of characters there are very few annoying characters and enough development with the good to over shadow the bad. While the opposite is true for me with FF8. All the characters were pretty bad: much too similar in background, characters who seemed to perform actions totally different from their defined character, boring charater design, and just "there."