Since these portraits are expensive in terms of art costs and system resources, we initially decided to only make four portraits, and crafted the story around a four person human party. When it turned out that we could afford to make a few more portraits, we decided to stick with human faces to give people a variety of human faces to choose from, as well as to avoid warping the story. Might and Magic 6 uses a skill based character system. No class has access to all the skills. Only Clerics and Sorcerers, for instance, can use Light and Dark magic, and Knights can't use magical skills at all.
Some classes have weapon and armor skill restrictions, as well.
It depends on the character you're talking to. Wandering NPCs have the most generic things to say, and they change their text daily depending on what kind of person they are and where in the game they find themselves. Main story NPCs have specific, complex things to tell you, and they'll react to story developments in topics they're concerned with. If you're standing in front of a dragon, for instance, you'll actually have to look up to see its face as it breathes fire on you. There are quite a few such huge monsters in the game.