Super hyped for FF12 HD, and all of that hype is because of the IZJS. I played the fan-translated (fan-localization-port?) of FF12 with the proper Job System it basically fixed all the problems I originally had with vanilla FF12. The Job System adds a lot of meaningful choices in character/party building, and also Esper allocation. Not to mention actually making Quickenings and Espers worth using beyond the earlygame. And fixing a lot of the dumb shit like how opening random unmarked treasure chests somehow locks you out of the best gear in the game. Or giving you said gear at like the halfway point and thus destroying all the challenge in the main storyline.
There's just a ton of excellent balance changes. It's like if Laggy modded FF12. Doesn't fix the story/character problems, but the gameplay is just a lot more challenging in good ways.