If I recall DX3 takes place 25 years before the events of Deus Ex. 25 years; People did wear different clothes 25 years ago, the world did look different. Still, I do understand your point of view. The legs of that one male model look like sticks. What comes to the cities and clothing and such, they might have wanted to avoid making the game too similar to the prequel.
Don't judge it (too harshly) before it's ready.

I wonder when we get to see pics of Thief 4.