Originally Posted by ?????
What, precisely, do you consider to be "deep"? The characters were fairly realistic in that each had a distinct personality, as opposed to some of the earlier games, where it almost felt like the script was being read entirely by clones. Some characters didn't have as many layers of complexity as others, but that happens in the course of nearly any story, and in real life. Not everyone is concerned with being "deep"; they're merely concerned with doing whatever it is they want to do. This shouldn't be looked down upon for not being more complex; it's the operative mechanism of all lifeforms, and it's fairly simple.