Whoa that’s a long post you linked. Let’s see if i can get to an understanding quicker by discussing with you here rather than reading that in detail.
Taking it piecemeal:
What do you mean by empty payload ? Which fields ?
[Edit:
Currently the above is only for POSTs because DELETE is not used (or even implemented in case of AppendableData) - there’s a potential problem of replay attack, but that is not what you seem to be talking about - so would like to understand your take on it.]