Or you could be really radical, but the game would likely die fast.
1. Eliminate the economy. Remove all trading, the AH, everything.
2. Make crafting reflect that there is no trading. Skill ups should be increased drastically. Farming for mats for "common" stuff should be much easier. Farming mats for much of the better stuff also made easier and everything solo'able.
3. Make all content doable with a single 6 party consisting of one real player and 5 trusts. Make the trusts available more diverse in how they function such that some content would need (or really really benefit from) using specific trusts or combinations of trusts. The game should make determining the correct trust combinations easier to figure out.
4. Make all the upgrade bullcrap adjusted to the idea that players would all have to farm all their own materials for everything. If they want something to take a certain amount of time fine, but it needs to reflect the changes above.
5. Watch as people "finish" the game and then leave.
Honestly all online games who try to have "real" economies have these issues. The only solution is to design your game to not have a "real" economy. Real economies suck, just like in real life.