Gear swaps. Unless you like the idea of hitting a swap macro, and at the same time your pt loot distributes and fills your inventory to max and <insert your favorite, hard-earned piece of gear> goes poof into oblivion.
Actually i think they would have something built around that.
Also quests are a bad idea unless they are not too difficult and the items are rare/ex. The gobbie bag quests were ridiculously abused because the items were not that common and the people that did get them sold on the AH for outrageous prices. Part of this was due to the fact that the areas with all the quest items, with exception of dunes for subjob items, were not highly visited areas. The game kind of limited enemy count in certain areas and overpopulated others. This basically forced people to find camps in the most highly efficient areas and not even bother looking at the others as they had no tangible benefit to being there...
The subjob quest is a good example with getting the magicked skull. It was not easy to get and trying to get some help could be quite a lot of work. Often you would get denied parties because of lack of subjob.
There needs to be the right balance and they need to build it so it is still doable in low population and off-hours. Which is exactly why FFXI had problems... off hours killed any casual players. Edited, Jan 25th 2010 2:05pm by boriss