Archetypes are simple by definition. If you'd like more complex characters, you'll need to move away from the convenience of archetypes and into the world of complex characters. Complex characters are not difficult to create--it's just a matter of choosing their component elements in the Build Characters window. "Complex" refers to the degree to which a character's internal and external characteristics are in harmony (archetype) or at odds (complex).
Personally, I think Dramatica's description of story is far from simplistic. It is rich in depth and breadth. Please do not use the StoryGuide as an indication of Dramatica's reach into your story. The StoryGuide is DESIGNED to be simple and linear because it is designed to be used by Dramatica newbies and therefore uses the archetypes instead of suggesting more sophisticated character choices. However, Dramatica need not be used in either a simple or linear manner. Look to any of the other Query System topic lists or the Story Points window to get a better idea of the Dramatica's scope.
For example, Dramatica does NOT describe characters such as a Hero or Villain. Those are storytelling conventions that are not very useful if you want to do something even slightly less conventional. Instead, Dramatica see characters as having functions in different areas (throughlines) of the story. By separating the functions, an author may combine the "pieces" in interesting ways to create non-traditional characters. By way of example, you may combine the Main Character with the functions of an antagonist or a sidekick or any type of complex character instead of the typical MC/protagonist pairing.
With that said, Dramatica IS best used to develop a particular form of story--one in which an author wishes to present an argument to an audience in the form of a story. If you're not interested in developing a "Grand Argument Story" then Dramatica may not be the tool for you to use. Otherwise, it's by far the best story development tool available and the only one that makes suggestions about your story based information you give it in areas of the story you DID NOT describe.