The whole eye thing is more along the lines of giving something relatable shape. Although I use the term "eye," in thos instance with robots I more meant "sensors." if you consider some simple robot designs such as Wall-e, his eyes are cameras. Alternatively, Eva from the same movie doesn't have functional eyes, but rather scanners and sensors elsewhere, and from our view of inside her head, reason to believe her screen that displays fake eyes to be close to where her actual scanners are. Perhaps her usual camera is behind the glass which displays the lights.
Nonetheless, you're right that a robot doesn't need to have eyes. The more I look at it and try to find my problem, the more I'm drawn to the top of the neck and the main sphere shape of the head. It feels as though the difference in depth forward between the front of the head and the neck is small, which then causes the head to feel flat. That then conflicts with the round shape and shading elsewhere...
Oh! I found it! I think I figured out why I was reading it wrong. Correct me I still don't have it right, but is the head is only the skull shaped component, and the rest of the parts coming off the neck are more like a tall collar or head/neck gear of some sort? I've been looking at it as though everyone coming off the necl was a part of the head shape, and those two almond-shaped holes were around the position of where eyes would be if the neck gear were cheeks/side of the head.
Maybe darken the bit of shading you have around those two wholes to further emphasize their depth and the more skull-shaped head, rather than a cut sphere? Also changing the background to a slightly more noticeably different gray or a slightly tinted colour may help show it? The skull shape is enough of that familiar shape idea I harped on earlier to not need eyes.
