i like the style of the models =) However the textures i agree needs more work.
Just a comment about the textures since your're working on it
Evey material and object will wear & tear over time. So by adding details on the texture, it will make things more believable.
EG. Soles of the shoes which wear and tear. Dirt on the Shoes
EG. Sweat stains round the collar
EG. Imperfections on the face.
Eg. If a character is a warrior. You can consider blood stains and the colour of blood overtime.
Eg. For your Enginner, his face should be more oily(high specular) Oil stains on his uniform?
These are little cues to start you for texturing