For the most part, the WoD professions design worked pretty well. Having a separate building for each profession, generating a limiting reagent through work orders, and allowing limited access to a profession you don't have, all worked reasonably well.
The major flaw with professions and the garrison were the mine and herb garden. Granting free access to these resources for everyone led to a lot of busywork. The mine and garden are the leading cause of the "chore" feeling of garrisons. This design also devalued the gathering professions.
By default, it would have been better if the mine and garden only provided extra automatic garrison resource generation, with higher values as you increased the building level. That would make it worthwhile for everyone to improve those plots, but otherwise they could be ignored.
Then add two new small profession buildings. A smelter and a nursery, or similar. Creating these buildings allows you to mine ore from the mine or get herbs from the garden, respectively. Then with the level 3 building, you could get Savage Blood or Felblight from mining and herbing. (You'd probably have to rename Savage Blood, though.)
Essentially, these buildings would make mining and herbalism the same as the other professions. If you were interested in those professions, you could choose the building. If you just wanted extra resources, it would cost you a small building space. But not everyone would be interested, and not everyone would feel pressured to collect their "free" resources.
The current design is deeply unfair to gatherers. They spent one of their two profession slots on the gathering profession, deliberately eschewing another crafting profession. It was really unfair of Blizzard to give that benefit to everyone else at no cost.
This would probably decrease the supply of herbs and ore, and material costs would have to be rebalanced across the professions.
Other than the mine and farm, Savage Blood is the only real issue with professions. Where ore and herbs are too plentiful, Savage Blood is too rare, and pushes crafters towards the Barn. Felblight is a better design, being spread to all the gathering professions.