I don't see how recipes make any sense. Most of the time you learn a recipe once, and then craft the item once. Ever. Because unbinding it is ridiculously expensive, kills any possible profit from making an item for sale so that people don't have to buy their own infinite-use recipes.
Two possible ways to alter this situation (having extra and useless items):
1. Remove recipes as they're not really needed. Simply add portion of its cost into item craft costs and make it possible to craft more items in specific places (forge at depth 18, for example, or specific forges in Hall of Heroes).
2. Make recipes 1-use items. Each time you want to craft an item, you have to get its recipe. Add a cataloge of items so that players know what recipe they need.
3. Remove recipes and make forges in Hall of Heroes, or simply make it possible to craft respective items in Hall of Heroes, near respective traders (who, for reasons unknown, are called "heroes").
Boss recipes? Add them to Hall of Heroes.
Krogmo coin recipes? Add a forge to Hall of Heroes that allows krogmo coin items be made for a small amount of krogmo coins (instead of 300 per 5* item take, for example, 50 coins total).
I'm against filling up the game with unused items/mechanics. Games shouldn't accumulate lots of pieces that were made obsolete over time with updates.
In real life, if you learn a recipe for cooking or crafting or something like that, do you really only do it once? You still remember the recipe to make it twice, millions of times, Billions.
And such as here. Selling recipes, those people remember how to use and make the items the recipes say. So if you can sell it millions of times?
1)Recipes are needed. Nuff' said.
2)Nope.
3)Nope.
I give this recipe idea a -1. Sorry.