For me it is this:

1: Increase the XP-Gain for gathering classes, so the market is not flooded with items. I mean Gatherers collect alot of stuff just to level up. Crafting classes don't need that much materials to level up.

2 :Let crafting and gathering classes unlock guild leves. I'm stuck at my Botanist at level 37 now because my BLM is not high enough to unlock new leves. I don't want to get forced to level my BLM first.

4: Make the game more dependent on crafters. I mean you get Gear for free when you're doing quests. Buying gear from NPC's is way to cheap. I could imagine lots of ways to make crafting more viable but thats not my part.

5: Gatheres and Crafters should really have more quests. But I guess that's something the development team doesn't have in mind. It might have a very low priority.

6: GP really need to get adjusted. It's boring as gatherer to use skills and the GP recovery is damn slow especially when the good skills cost almost all GP you have.