All dungeons no longer earn spirit bond points on gear (minus the first point of exp to bind the item). Spirit points are contained in an aetheric crystal you can then use to charge up gear.
Basically, imagine Elderscroll soul stones/crystarium (FFXIII) point charging.
To ensure players don't load a crystal full of exp on high level dungeons and load it out on low level equipment, make tiers that follow the tiers of materia/gear level. So Aether Dust is tier 1, chunks 2, shards 3, crystals 4, and cluster 5 (and each collects aether of the appropriate monster level tier, and so you are still spirit bonding at an appropriate rate). As an aside, I'm a bit leery of what will happen to all this tier content over time- imagine if we get level 80 stuff years from now.. thats 8 tiers of materia, catalysts, and repair items. Some sort of dynamically scaling items might be nice.
I imagine how to best implement the system is to have a quest unlock it, perhaps pieces at a time, what it would look like is a little bar near each part of your body on the paper doll. Each part earns aether as if it was a gear piece- you can then choose to unload that aether infused in yourself onto other items to spirit bind them. So functionally no different than before except for the fact you don't need to wear them anymore. If you used this idea exactly you could just have a menu for extracting abundant aether (aether collected)- and the system would remember how much exp you have from each tier and allow you to extract the tier types you need/wanted when available.
Anyway, in this way you could go with your best gear- earn points as you normally do, not be a burden to others and yourself, still work the same amount of time, maintain the use of dungeons (spirit binding is useful in dungeons, you just aren't ruining it for others- this keeps the content alive) and still use the same materia system without major revisions.