perhaps have a store which gives the potential for peeps to craft two weapons together of equal or greater level. (E.g. the base item which your modifying is the lowest level item)

this could do either 3 things:
-->Supply a load of heat to items, e.g. mixed items give heat to the base item assuming you want to level it up faster.
-->give new attributes to weapons. E.g. Say you have a weapon which could deal a fire status effect, and you want a make a weapon which does deal a fire status effect but cannot. Well at a small cost to your overall damage you can. however, the fused attribute will only remain at the same level as the item you mix them at. So, persay you have a avenger, and you fuse it with a 1* cold-snap, then it will only deal the 1* cold snap status effect, even if you upgrade it to divine avenger. if you craft a weapon (Base item) with an armor which gives an ASI, or CTI, then that is applied to the item. The greater the effect your applying, the greater the damage reduction. e.g. applying gran faust's effect will have a huge damage reduction applied.
--> a random item equal to the average level of the two items, rounded down.

both items are destroyed in the process, in return you get a new item which is the same type of the base item (E.g. if you used a gran faust as the base item, it will always remain as the base item) with new features (taken from the other item).

mixed items cannot be remixed. This stops there being a "perfect" weapon, with all the status effects.

Pros of this:
New range items --> stops people asking for "this version" of "this weapon"
CE sink, a huge one
Heat sink