Yeah...he needs a couple of more bars....but, while maybe a little different than what we're used to seeing, I think is pretty well engineered....and with the addition of some small gussets should be very strong.
Let's see what else he has in mind...he may be trying to avoid traditional bracing for certain accessibility or comfort requirements.
Some of what I see: the front bars are triagulated to resist front to back crush....the biggest weak point I see is at the frame...thats where I would put a short bar angling back or one running forward....
The back has angled corners to help resist crush laterally...some gussets and one angular bar would help that....in the same vein, the front has a half bar for the steering support....again...making it go side to side on an angle would still give that open leg room I think he was going for and give the front that lateral support....
But mainly....gussets, gussets, gussets.....highly underrated, unobtrusive but extremely effective.