Materia melding is really a failed design because it is not about customizing your playstyle (it changes too little) but about creating a barrier of entry to end-game content (you need to look up a guide and meld accordingly if you want to raid seriously, or you need to do the generic meld rule-of-thumb if you're not raiding progression). So as a means to customize your gear, it is a complete failure.

The easy way out, really, is to detach materia from combat, make them utility only. Summon mounts faster, teleport costing less, etc. Make no mistake, I would prefer if materia would modify our rotation to create different playstyles, but eventually someone is going to do the maths and we're all just gonna end up with that one optimal meld+rotation for each job. To re-do materia balance every patch is not only a heavy burden to development, but also an unnecessary disruption to player experience.

So I seriously would push to revamp materia to be non-combat.