Whether you want to attribute it to skill or not, high-end gear should always be a group effort. This is a MMO not a solo game. Unless the "raid" gear has some special effects to it materia can never have, any type of group content will lose the point to doing and thus we're left with the epicness of town crafters creating the best gear available. This completely eliminates the need to even go outside other than to gather and spiritbond grind.
Double materia isn't even that difficult given the probablities. I already have a full set and it took about a weeks worth of time to get (tier 4). Over time even triple won't be that uncommon. Where does that leave us? Raid content being that much easier due to it being balanced around 1 materia slot gear.
It's a fail system that needs to have more limits than it has currently.