From a quick look, the only change I can spot is a curious one to rule 4(f);
4(f) Only one international departure and one international arrival from/to the country of origin permitted
EXCEPTION: Two permitted for origin USA when one arrival-departure is a transfer without stopover.
NOTE - Travel between USA and Canada is not counted as international.
No more than 4 international transfers from the one country permitted
My
emphasis
I think this change can only apply to Nth American countries, for example:
...NRT-JFK-BDA-MIA-BGI-MIA-POS-MIA-SCL-xJFK-LHR...
has five passes through the USA. It makes use of the allowed six flight segments in the continent and also makes use of the allowed second visit to the continent.
Other continents are restricted to four flight segments, so it is not possible to have more than four transits of a country
And anyway why is the restriction in 4(f), which concerns only the continent of origin
??