Designing an android's head (I)

I've been designing an android that will replace the current body of the player's avatar, which is one of the few 3D assets that was still provisional. I wanted to go for something classic, neutral, not too original.

1) My starting point was this simple sketch.

2) I added some detail and "humanized" the face. And that was the problem, it looked like a guy in a suit.

3) I removed the nose, added some "ears" and made the face look more like a skull. Now it looks more like a robot, but the eyes are still too "organic".

4) I modified the eyes to make them look artificial, but still maintaining some of the "organic" essence. I also made the "skull" appearance more subtle.

5) Finally, I played with the result a little bit to give the robot more "personality". I am not entirely sure if I will keep this version, but I think it achieves that goal.