I think they were pretty cool. Especially in in the gameplay department. It was sort of like a mix between Kindom Hearts style monster confrontation, as well as the final fantasyish abilities, but not like final fantasy the possibilities weren't all that limitless.
Nonetheless i think they were cool.
I also have to disagree about your statement on how the 4 games should be 1. I mean just think about it. Each game (in the beginning) came with a DVD of a case related to the game. So if it was all one game, you would have 4 different DVDs and 1 game, which is an odd thing to find in a game case. Also, did you think about how long the game would be for it to have to stretch across 4 games. It would be like playing a semi-Final Fantasy game. So there's my thoughts.