This new 'Materia' system is sounding more and more like a hybrid between WoW's enchanting and gem socketing systems.
It's also going to encourage a little trick done in WoW to skillup two professions at once.
One common profession combination is Tailoring and Enchanting. You use your tailoring to create pieces of gear that can be disenchanted (getting tailoring skillups). You then disenchant the gear (which destroys it and extracts enchanting materials). You then take your new enchanting materials and enchant your good gear with it (getting enchanting skillups).
If this is more of the intent, to make the more common gear able to be broken down into materia, it makes perfect sense. However, the whole affinity aspect (meaning I have to wear the stuff) still seems a little wonky.