All crafts are interdependent, though some more than others.
For example, all crafts need the Toolcrafter for missing or replacing worn out tools. The Toolcrafter needs some items from the Tailor, Basketweaver or Leathercrafter for a few recipies/patterns. But the toolcrafter, while important, won't be in high demand as other crafts because tools don't need to be replaced every day.
I definitely like the idea of one character per account. It's something I've never really had any experience with personally but I can see a lot of the positive arguments to having the game this way. It will basically force a true player economy into the game as compared to everyone being able to be nearly independent in terms of filling all roles they need to be competitive. I came over from Mortal Online as my guild is thinking about moving here and I see Xsyon being a lot better and keeping people more involved and happy.