Chris S. Sims of Critical-Hits and formerly of WotC joins me to talk about how to re-skin a character so make the PC you really want, without restriction of rules. We then demonstrate those ideas when we build a warforged shaman.
To answer your question, in my game the monster’s do tend to attack the spirit of the Shaman, rather than attacking her. Two reasons for this is a) she dose tend to stay in the back of the group, being a squishier character (she only gets into the main battle if she moves there or the party is surrounded), and b) while smarter monsters might figure out that she is controlling the spirit, it’s often hard for them to get to her and if they do disrupt it, it goes away and then gives them a better chance to get at her. That might be just my DMing style, but all of my monsters tend to be more intelligent and will often run away instead of standing and dying.