As of right now, metal is essentially useless to a player, unless they are using it in a street project. Here, I would like to outline my ideas for the uses of metal and some other miscellaneous ideas that relate to it.
Uses of Metal
As you know, metal must be smelted into ingots. Then, it can be used to create tin, copper, and molybdenum. These metals, as I mentioned before, are useless. I would like to suggest the creation of a "Metalworking" branch of skills. Then, when you click a tool such as a pick, you could choose "Reinforce." This would let you upgrade the tool with one of these metals, changing its appearance, durability, and possibly its other usage attributes. Then, you'd have to smelt the tool down before you could upgrade it with another sort of metal.
Spawning and Smelting
If these ideas were to be implemented, the value of metal would probably increase. The frequency of metal ore deposits would have to adjusted. However, if a player has sought out metal I think the smelting rate of them currently is ridiculous. It should rather be 2 or 3 chunks to an ingot.