I think there are two things that need to be fixed for this.
First, a crafter probably only needs to start a project when he has all the materials available. As it stands right now, they will grab the stuff and dump it on the workbench, then wander around until the last part is available. This, I assume, occupies the workbench, making it so nothing else can be done. This probably needs to be changed. I say probably, cause there could be a good reason for doing it the way we are now, but I just cant think of it.
Second, crafters need to check the job list intelligently. The weaver is easily the best example of this, because he is the most expensive guy resource wise right now, and any problems with the way crafters work are readily apparent when it comes to him. So, the best way to ‘automate’ the weaver is to set him up a series of maintain orders. Start with 10 or 13 spools of thread, then three rolls of cloth, then three leather rolls, then whatever final good you want. With the way the job system works right now, the weaver will:
Craft 13 thread
Craft a Bolt of cloth
Craft 3 thread
Craft Bolt of cloth
Craft 3 thread
Craft Bolt of cloth
…
Craft worker uniform
Craft 1 Thread
Craft Bolt of cloth
etc.
This basically automates him. I usually do a high amount of thread, because it gets used in several other recipes as well, but you could do with just 4 as well. The issues crop up when there is a shortage of supplies. If I dont have enough to make a thread, the weaver will get stuck on that job, even though I have excess in stockpile for him to do the next job. He doesnt skip to the next task, just gets stuck on the current one. This process will get extremely frustrating later on, when you are making things that require bits from several different sources. If a job cant be completed, the crafter needs to check for the next one in the list, do that, then check if the original job can be done now. It doesnt make sense in the current implementation.
EDIT: Even worse, if the weaver starts making cloth, but someone else uses one of his threads and he has none left, he will just herp derp and stand around.