Crafting in this game is limited to the weapon mods. I get that because it is not the sort of game where crafting applies so the salvage and mod system is very basic. However, I think some small additions could be useful.

Ways to combined mods or mods and arcforge so that you can make a better mod or change it to the type of mod you want would be nice. For things like sights, I would find this very useful. On full-auto weapons, I want sights, not a scope. Most of the drops are scopes. But if I could use some combination of multiple scopes and arcforge to "make" a sight that does not obscure vision like a scope, I could "craft" what I want out of drops and possibility even improve the rarity by one step.

The ability to take multiple weapons and make one new one out of them would be nice. Have the base stats and nano effect be from weapon A and the Synergy and Mods be from weapon B. A+B+some acrforge = new weapon. The question would be how to deal with rarity. Average it? Lowest of the two? Highest of the two? In any case, it would let people customize their weapons more at the expense of their extra drops.

A good example of why this merging weapons would be useful is when the synergies change. You have a weapon with 1 or 2 mods and now you can't get those again. But you get a different weapon with full mods, but it does not have the base stats and nano effect of the old one. Being able to merge them would be nice. Or, being able to get a new, perfected weapon and then plant you synergy and mods from an older one onto it.

Obviously they would need to be the same weapon skill group for this to make any sense. Transferring from a pistol to a rifle is not logical. But merging two pistols or two bolt action rifles or two LMGs, etc. does make sense.