I actually would love to see some way to add group crafting. Why not make crafting leves linkable just like fighting leves? Increase the numbers of required synths during the leve to match something appropriate to the party size and give a party bonus for completion.

In order to prevent a crafting party from turning into a 1 person show with several others sitting around soaking up the free synths, perhaps the synths could be randomly assigned to every player in the group - so if there are 12 synths and 2 people in the party, then each player would still have to make 6 synths - but both players would get completion credits for all 12 items. I liked the above suggestion of granting some sort of crafting party buff as well.