There's nothing really to "throw away" that would make it slighter and smaller whilst still keeping your desired feature set.

The reality is that you're using the VR/AR features in one specific way - not that you're not using VR/AR

It's possible a slightly weaker CPU or GPU could be used but I don't think so and in any case the effects of that would be on cost not on weight. And I don't think the difference would be significant.