In WoW gaining XP, gaining achievements and gaining gear drops includes gameplay. The gameplay in WoW is pressing hotkeys that cast spells on a monster until it dies, while avoiding some bad things on the floor. If you do the gameplay on the expected level, you get reward. If you are better, you can complete more challenging monster fights to get the loot. Sometimes some flavor gameplay is added like using cannons to shoot down … birds trying to eat baby turtles and other stuff, but even that is some form of active clicking for some reward.
Gathering professions are also based on gameplay: you wander around in the world, find node, kill monster that guards it and gather it. It could be translated into a world quest where the monster around the node is the quest completion criteria, while the ore or herb in it is the reward.
However crafting has no gameplay attached. You just grab the materials (gathering them can include gameplay but that’s irrelevant) press “craft” and you’re done.
To make this thing more engaging, recipes and crafting levels are often added which are to be gained by gameplay. However there is a fundamental flaw here: getting the recipe/level includes gameplay, not using them. You need to do gameplay once, but then you can craft the item forever. This also means a permanent split between those who have done it and those who have not. The former can mass-produce items, making stupid amount of gold. Of course if enough people do the recipe-gathering gameplay, then no one will make gold, since the cost of the actual crafting is a single mouseclick after the initial (and already sunk) cost is paid.
Any kind of band-aid just make it worse: for example WoW has daily cooldowns on some crafting. This doesn’t help with the fact that still no gameplay is added, but now players must wait which they hate. Also, this can be – and usually is – bypassed by using masses of alts.
I’d like to point out that the problem is unsolvable unless crafting is somehow turned into a gameplay, one that the players enjoy to do. For example actual crafting involves hammering the item using various actions. If such meaningful gameplay can’t be designed, I believe the best course of action is just ditching the whole concept and let NPCs do the crafting: you approach NPC with materials, select recipe, press craft, come back later when the NPC is done.
No point trying to solve the unsolvable. No matter how heretic the idea is, player crafting with professions and recipes is better be gone.