The 23kg baggage allowance for *G members has been around for at least 1-2 years. Itīs consistent with the *A rules which stipulate "1 additional piece of baggage where the piece concept applies".
Itīs nice that AC still allows 32kg per piece for Es/SEs. Most FFs usually donīt check more than one bag anyway (if any), but itīs nice not having to worry about it on the one occasion when you need to check a load of stuff.