I don't see the big deal. 73Z is already packed tight with 398 seats. Who cares if 27 seats get added. It would be one thing if J was already a lovely experience and now a downgrade is coming.....but

....in fact, J on 73Z is probably the most unpleasant of any bird in the CX fleet, it's oversized plus there is the dreaded middle seat in J which is exclusive to the 777-300 and 777-200 regionals.

If CX achieves those 27 extra seats capacity by downsizing J and thus making the cabin a little more pleasant, I'm all for it. The plane already is full blown cattle car status, 27 extra Y seats in favor of fewer J seats might actually make for a nicer ride. Y will hardly change and J could actually feel quite a bit nicer.