I don't understand why there is such a huge emphasis on "spammy" recipes in this game. Having just started out, attempting to level my professions, I notice I have to rely on singular crafts as opposed to group crafts.
TLDR Version: Crafting is too "spammy" and focused on single input crafts. Crafts requiring more inputs should give more exp.
I know some people will tell me I don't know how good I have it, having started after 1.19, but I did do crafting in beta (made bronze mitt gauntlets and a bronze barbut). And keep in mind just because it's better than it was before, doesn't justify what is still a system with fundamental flaws.
As an example with carpenter.
Like any reasonable human, as a carpenter I spent my lower levels crafting lumber. Now, to craft maple lumber there are two recipes: 1x maple log, 1x wind shard OR 3x maple log, 3x wind shard. Both recipes operate on a 1:1 ratio, 1 maple lumber per maple log put in.
So, what did I have to do to skill up? Craft 60 maple lumber, one at a time. What would have been nice? Being able to justify using the 3x maple log recipe. Why didn't I? Well, the 1x log recipe gave 300 exp, the 3x log recipe gave... 300 xp.
The same can be said about other jobs, though sometimes not as egregious (for example, when making iron ingots it's either 3 for 1, or 8 for 3. the 8 for 3 is better volume than 3 for 1, so kind of justifies its existence.)
The same problem crops its head when considering skilling up on other things. Why make recipes that take 4 materials when you can make ones that take 2 or 3? And that's ultimately the problem. The system greatly favors "spamming" "small" crafts, crafts that take 1 or 2 materials.
How the system should work: The exp you gain after a successful craft should be proportional to the number of inputs. As a formula, something like 200x number of materials x (Craft Level / Skill level)*. (* The craft level / skill level ratio is just to indicate that as you outlevel crafts, the exp goes down, while crafts above your level give more exp. It doesn't need to be the exact ratio, and would probably be more complex in game).
Going back to the maple logs example, the 3x maple lumber recipe would give 3x as much experience as the 1x maple lumber recipe. It would also encourage people to craft more complex items to keep or sell while skilling up, because the more materials, the more experience to be gained.