Just a last remark from my side on the above.

I do not argue that your proposed circuit does the job. Just as you do, I try to design circuits that "work". However, I have a simple and straigthforward approach to embedded designs: if I can solve it in software, I prefer it above hardware.

Having said that, I agree that unexpected behaviour is to be avoided at all times. Just like anyone I hate manuals, so I prefer to make things that can be used without reading anything.

To solve the "unnatural" behaviour exposed in this case, the system can visually switch off before the device is actually powered down. Simply blank the display, switch off any other visual indicators and blank the display: from the viewpoint of the user the unit is powered down immediately. The fact that the controller will then sit and wait for the power switch to be released takes place behind the scenes. Nothing unnatural here.