Here are the schematics of what this system will do to the balance between crafters, gatherers, and battlers.

Right off the bat, crafters benefit. The first step of making a materia'd gear is to purchase something from a crafter to start turning into materia. Battlers and gatherers start off by buying multiple things from crafters.

Battlers -1. Gatherers -1. Crafters +2.
Battlers finish their materia and sell it to crafters.
Battlers 0. Gatherers -1. Crafters+1
Gatherers gain catalyst and sell it to crafters.
Battlers 0. Gathererrs 0. Crafters 0.

Now. Crafters by the books now own:
All the gear.
All the materia.
All the catalyst.

AND THEY ARE EVEN WITH GATHERERS AND BATTLERS.

Crafter combines the cost they incurred by buying the catalyst and materia from players and use that as their base selling price for just straight gear.

Battlers -1. Gatherers -1. Crafters +2.

They mark gear up for rarer combinations.

Battlers -2. Gatherers -2. Crafters +4.

They charge 1000% return on epic pieces.

Battlers -???. Gatherers -????. Crafters +???

Crafters essentially own this entire market the second it starts, and cannot ever. EVER. Not come out ridiculously on top.