I think most people are in agreement that finding items you need for both crafting higher level items and gear is near impossible. This could be best solved with either a retainer search, an auction house, or global trade chat. Two of these require intervention on SE's part, however the global trade chat is something we can do in-game right now with a little work.
I've had the idea since open beta of creating a linkshell and trying to invite as many people on the server as I can fit into it, for the purpose of buying/selling of crafting materials and finished products. The XIV LS system goes a long way towards making this a possibility, with the ability to equip multiple linkshells.
The problem I've had is that I can't seem to find enough people in-game who are interested, or a way to properly advertise for the linkshell inside of 85 characters. So I'm going to start here and see if I can get some traction for this idea inside the community.
Also if you like the sound of this and are on Rabanastre, hit me up and I'll work on getting a pearl to you.