I dislike the term 'Materia'.
This is a term that feels exclusive to FFVII and just doesn't fit into the FFXIV scheme. This new system will not be the same as FFVII's Materia system, and should not be named so. It would make more sense to use something that ties it into FFXIV's aetheryte.
Some suggestions in this thread have been made such as:
* Aethecyte
* Aethercite
* Aetheria
* Aetherstone
* Aethergem
* Aethershard
* Aetherlith
* Magicite
And those are just a few from this thread. There are many many options.
Other aspects of Final Fantasy have remained throughout the series, but have gone by other names, to keep them appropriate to the story. Such as the avatars (summons, espers, guardian forces, primals, etc).
I would rather see this system adopt a name more unique to FFXIV that will help it fit in with the game and story. Materia just does not fit.
Please consider changing the name of this system!