Materia system should be streamlined and based on FFVII.

[Zetsumei_Tsunarashi]

I think they should just make all gear going forward have a predetermined number of slots in it and putting materia into those slots has a 100% success rate all the time. Thus gear with more slots = better.

Make obtaining the gear hard, not putting materia in it.

For crafting make the recipes for multi-slotted gear progressively more difficult. 1 slot is a regular synth, 2 slot you need a lot of mats, 3 slots you need a lot of mats and you have to HQ the synth, 4 slots you can't even make it unless you have some recipe that dropped off a boss or something, 5 slots same as 4 but you need to HQ, and use a kobold forge or something.

Then have gear drop from raids with varying number of slots. Darklight type drop rate items has like 4-5 slots, and go down from there.