Here's an idea: extend the time it takes to craft things to be more realistic. This would make it generally impractical for normal play, so allow PCs to queue a few crafts to be performed while they are logged off.
The result? No more spam crafting of various goods, greater realism while at the same time not making crafting unplayable.
Got an example?
Prep craft sword.
It will take X ooc time to complete.
Log out.
X time later.
COme back.
Sword is completed or broke.
That idea?
Just do all your spamcrafting at the start or end of your login session, and say you did it while you were offline.
I like the idea of OOC timers set on things like the RPI codebase, except that it doesn't really fit with how crafting and skills work in Arm. I'd love it if Player-crafted things were higher quality than the no-craft items in the database, and were rare on a "I can't make more than a few swords a month" mentality. But things would NEVER be crafted and skills would NEVER improve.