Maybe you (and people in general) can work together. The J2HG crew has quite some experience with some aspects of manipulating JJ2. And some of them (like Link) know C++. The biggest problem is that most people use different programming languages here.. and in J2HG. I for example would make this stuff with others but I only know Delphi (excluding internet scripting languages).

This thing would never get off the ground without multiple people working on it, probably. Too much testing and designing work. Designing a sustainable scripting language that will be logical even after features get added isn't THAT easy.