I actually created the system when I first joined KH. It was based off of what they had, with some minor adjustments that encouraged playability at lower and higher levels of posting. We gave the system more MP/Chi, and were less rigid as far as the general rules went.
It still works the same way, it's just different....more newbie friendly, imo. FFWorldz jumped up quickly when it first started because of the system we put into place.
It wasn't made before it (the party members and ships were originally our ideas however, as well as the old stat system that KH used to use, that we reintigrated into the website for the sake of making it easier to understand people's strengths and weaknesses.)