How is it exploitable? How does crafting lead to gil selling? Last, I heard, gil sellers are using DoW leves not crafting.

Most of the other classes stand at about 50% crafted with 20% GC 30% drops.
Again, a vague number, but it is clear that the ratio is still skewed to work towards crafters.
That's 50/50. O.o how is that skewed.