I'd prefer to carry the weight on the back or as a necklace or a collar than all of it on my head.
How thin display port cable could be if it was optimised for sinhle purpose and lenght of up to half a meter?
The difference in weight is phenomenal. I would absolutely love to have all of that extra stuff offloaded into a pocket pack. Or, at the very least, parked behind the head as a counterbalance.
Fair point w/r/t cooling. Again, I think distributing components around the whole head, rather than 100% on the face, is the way to go.
That doesn't add meaningful latency if bandwidth is sufficient. A 80Gbps bidirectional link (which is around what latest DP/Thunderbolt/USB handles) would work fine. You can always add more lanes if you need anyways, at the expense of a thicker cable.
I would still want it to be relatively lightweight, but you could go much heavier than on the head and have it still be comfortable