You can read the full list of changes up above but my summary is:

Basically, it's a Class Mod for FFVIIi where every character gets a GF which leans abilities with levels (or select items) and those are meant to be that character's and nobody else's. Zell has Ifrit and is a Monk so he punches trout, learns abilities like Mad Rush (Berserk/Haste/Reflect), Quistis is a Blue Mage so she has Shiva who learns the Aura ability (not a spell in this) and so-on. You can technically give a GF to whoever and have White Mage Rinoa use Black Magic but their stats are designed for certain roles and also it just kinda misses the point.

IMO, this is by far the most creative and ambitious FFVIII hack of all time. More importantly, it is fair. Early fights in other FFVIII hacks can kill you but as the creator of Crystal noted, fight difficulty should respond to player options. As you get more options, the game gets harder. Never impossibly hard or unfair but still more interesting and requiring more thought than the original by far. Like, since Rinoa is the White Mage, who do you send to the Missile Base and who goes with you back to Balamb Garden? That is basically a snapshot of the kind of thinking that goes into this mod. Right now I have to swap out Quistis for Selphie (Black Mage) because Bahamut is kicking my ass and I need her unique talents. (she is the only person who learns Double which is an ability and not a spell this time around and Bahamut has shifting elemental weaknesses)

Granted, I played v1.1 several months ago now. The mod has changed some since then. But still, here is a sample of the mod in action. He made my favorite character into an awesome boss at last.