What if the crafting system worked like this:
When you fight badguys, you get IGC and raw materials somehow. Never pre-made, fully usable Augments, just raw materials and IGC. So you have to go and do crafting to make the Augments you want from the raw materials you have or have bought on the auction house. Once you process the raw materials, your Augment or Refinement is now ready for you to use, but it's account bound at that point. You can't sell it. Once you slot it into a power, its then character bound and can't be taken out unless you buy an unslotter to do that.
So the auction house would deal primarily in raw materials, which are tradable, and come in different rarities, but actual usable Augments and Refinements would have to be made, never found. At least the good ones. Maybe you could still have really weak, disposable Training type stuff at low levels, but as soon as people try to move up to the "Double Origin Enhancement" level of gear, they have to start crafting it for themselves. Then maybe the "training" level stuff could still drop and could be converted into a raw material or two via a randomized salvaging process.
The idea here is to ensure that the item making process is basically a one-way door that won't allow you to just rent your gear then sell it all later, so that when IGC get's sunk by the game, it basically stays sunk.
R.S.O. of Phoenix Rising