I don't know why people hate the KH series. I mean, I'm not a huge fan, but I enjoyed playing Kingdom Hearts 2 immensely. The game was made to be fun and it does its job of ensuring you have fun.
Well, maybe except for the "Little Mermaid" bit. Ariel is hot and all, but I don't know any one who likes playing through 2 hours of you pressing the X button in a rythm game based on Disney music.
I believe one of the most underdog RPG's out there is the Shin Megami Tensei series, most notably the Persona games. Persona 3 was good and Persona 4 takes what was good in 3 and makes it even better.