Seems like they act as a gold sink and a way to build legendaries, and really nothing else. You can’t make any kind of profit off of them. Here are some suggestions that could make them better.
1. Make the top-end stuff soulbound so you have to take up that profession to obtain it for yourself.
2. Add special benefits for using a profession. For example, something like an extra ring slot for 400 jewelers.
3. Remove the TP fees for items posted that you crafted yourself.
4. The ability to craft special salvage kits which allow you get 100% of resources back on items crafted by the profession. For example, an Artificer’s Salvage Kit that can be used on a staff and be guaranteed to get back the Staff Shaft, Staff Head, and Inscription.