One thing about alchemy that really bugs me is the fact that all of the 3* items require you to upgrade from the previous item. The problem here is that the previous item is already soulbound due to the fact that I'm wearing it, so I can't very well trade it to someone and have them upgrade it for me. In order to get the upgrade, I'd either have to go out and find the recipe myself or get another non-soulbound version of the item that I already have. This just seems incredibly cumbersome, and I'd like it if it were possible for the crafter to perform alchemy on an item that is soulbound to another player.
Basically, I was thinking it could work kinda like Enchanting in World of Warcraft. Allow the person to put their item in a "Will not be traded" box, then the crafter can drag and drop that to the alchemy window and craft. The resulting item would end up in the first person's bag (possibly still soulbound).