I dont think you can simply make money by leveling battle classes and battle classes only. The only thing I can think of is farming, and I dont think that drop rates are that great. Maybe that will change with jobs that can up drop rates *COUGH*COUGH*thief*COUGH*COUGH*

As far as crafting goes, it can be very rewarding if you want it to be, but it does take a lot of work. Just like with anything: the more effort you put into it, the more money you will make. However, crafting isnt for everyone, and I definitely understand why some people avoid it. As frustrating it can get at times, I tend to enjoy it. Nothing greater than getting something great to HQ on NQ materials .

Maybe you want to do some gathering? Gathering is like farming in a way. If you can get a sense as to what crafters want/need, you can make some pretty decent gil that way.