My suggestions comes after seeing lots of players just grinding through crafting, mainly in chef one, just to get to 400. When you see their recipes, they only have 15 or 20 of them.
I, for one, like to gather recipes from all the karma vendors. I do like the discover system, so you can combine and experiment. But after thinking about it, it’s pretty much useless. Basically i can just grab a recipe or two, with magic find stats, and ignore all the rest. So what’s the point of other existing recipes?
My suggestion would be to earn achievments according to the number of recipes you have. 1 recipe? here’s an achievment. 20 of them? here’s another. 50? …and so on.
This could be applied to the other crafting activities, even with titles or whatever.