I agree. What they should do is give each class multiple specs and different choices in the skills they have. Perhaps, once you reach a certain point in the game, you could pick from two different class paths that advance your character in different ways, or "advanced classes," if you will. After that they could give us the option of specializing our characters in several different ways. Other games did this by using something called "skill trees." If each class had several of those, we could pick skills to define our character.
Try posting this in the suggestions forum. Maybe they'll add these features in 2.0.