I was thinking mabye instead of making whole new professions they could add a sort of specified option in some next chapters. Like you can do missions to make your character more specified in a certian attribure "I.e. Fire Magic, Axe Mastery etc..." so when you do them your character looks slightly different from the others and their specific attribute gets some sort of boost and you get access to special skills. That way you dont add in heaps of different classes but you get new stuff to fiddle around with. Just a thought.
Well.. its not really that related to the new proffession issue...
Easy way is to add profession related titles for the visual differnce... also wielding weapons tend to associate with what attribute you focus on...