The order of revelation is a historical fact not a religious opinion.
Exactly what the consensus of the scholars has been, that the order of chapters and verses is توقيفي meaning it does not follow any discernible rule; rather it was specified that way by the Prophet, peace be upon him, and he did not say why.
The abrogating should be lighter or equal than the abrogated. I do not recall seeing this as a rule in pro-abrogation literature.[/list]
I'm guessing here, but maybe he was thinking of بخير منها أو مثلها
(with what is better or similar to it) in 2:106. The argument was made that the abrogating may be harder than the abrogated and still be better because it offers more reward, for instance, or benefits more people, or stops more sin.
IMHO, the only valid validation rule
is whether the abrogated explicitly says it's abrogating and names what it abrogated. Our validation rule #0. That never happened in the Quran, but it did happen in the Sunna. Wills are contested in court if they do not explicitly say that they annul previous wills and are dated.