Materia Changes in 3.2:

[PArcher]

Materia would be cool if it gives actually interesting stats!
-hey this Materia adds +1 second to my Enochian? Hmm nice
- shortens cooldown for swiftcast? Hey this could be useful?
- effect of raging strikes increased? Cool!

And suddenly you have a balancing nightmare on your hands. And that groups WILL demand you to have very specific materia melded to your gear to be considered for a group, even low-tier groups (since stats like these can be game-changing, unlike the secondary stats we have now).

As interesting as it seems, it will not bring variety at all, with one stat set being the most powerful and the only one people will consider for any even semi-serious content.

EDIT: Sorry, it can actually be far worse than now; if a set is found to work better on certain fights, and another set with a different fight, you'll be required to have a set for every fight you intend to run. Imagine having to meld 4 sets for Alexander, one for each floor, and a set for each EX Primal. And yes, people would demand this...