We have this rather weird notion that there are global crafting recipes for making just about anything, and usually the most a particular object/item that helps with crafting is going to do is increase the size of the recipe space to give room for bigger recipes. There are a few exceptions such as the hoe in farming, which really does create new items when used in a specific way.
What if we did away with (most) global recipes, and just about everything were made with the assistance of one or more nodes, tools, or items? For example, glass bottles would be made using a blowpipe; stairs using a chisel on stone; tools by putting metal stock in an anvil's inventory and then hitting it with a hammer. Or something to that effect. With the development version's minetest.show_formspec(...) function, there's really no limit to the logic that could be applied to this from a mod.
The interesting bit here is that each crafting object would carry its own recipes, or even make imaginative alternate use of its inventory. For example, a stove might have a place for whatever kind of pot/pan/dish you are using, spaces for the ingredients, and a way to specify what particular dish you are making (since multiple dishes might use the same ingredients).
Any amount of realism or complexity would be possible, but even if it is kept very simple this could provide some interesting detail and a break from the monotony of sticking stuff in one inventory area and getting out one result. All kinds of uses pop up for new materials (aluminum pots and pans, anyone?). So, what do you think? Is the global craft registry ready to die a slow but painless death, replaced entirely by Lua mod code?