I think saying Shepard doesn't have emotional range is kind of ignoring or not understanding a important aspect of what limits his range.
The moral choice system.
The character is usually presented with three options to choose from when talking, and when your questioning someone usually five, and that's just for one response to a dialog tree of 5-10 on average.
So Shepard whos charecter is considered legally sane has to act like a normal human being. If the player starts off his response with the good option, and his next response is the renegade option, his tone has to make sense in the situation. You cant have Shepard trying to speak in a diplomatic calming tone for 4 responses and then on the fly at the on the 5th response start turning all dirty harry in his tone or seething with anger, when before he was being diplomatic. That's why his tone HAS to remain relatively flat in comparison to other characters.
That said, the male voice actor is atrocious even with his limitation, the female voice actor does a far better job with that constraint in mind.
The moral choice system.
The character is usually presented with three options to choose from when talking, and when your questioning someone usually five, and that's just for one response to a dialog tree of 5-10 on average.
So Shepard whos charecter is considered legally sane has to act like a normal human being. If the player starts off his response with the good option, and his next response is the renegade option, his tone has to make sense in the situation. You cant have Shepard trying to speak in a diplomatic calming tone for 4 responses and then on the fly at the on the 5th response start turning all dirty harry in his tone or seething with anger, when before he was being diplomatic. That's why his tone HAS to remain relatively flat in comparison to other characters.
That said, the male voice actor is atrocious even with his limitation, the female voice actor does a far better job with that constraint in mind.