I don't know if someone's mentioned this, but I would LOVE a system that lets you several put tier 1 materia and through a process create a tier 2 and so on. Branching out from that simple idea, it can be used so people can add specialization to their gear by "crafting" materia with different stats to make some hybrids. I'm not sure what the economy implications would be but ofcourse I'm not saying 2 tier 1 will make a tier 2 at 100% chance. Make it a risky process, and with a high cost.

One of the benefits I was thinking about is that with something like this implemented,there will be a bigger market for low level gear. (Which would help out people leveling DoHs) People can spiritbond low gear (which i believe spiritbond faster than high level gear) for a lower cost and let people who want to risk the process buy these low tier materia. And well, with that as a segue, this will also make the low tier materia market be more active once the servers get older.