Talk in the AC forum of new AC baggage limits coming into effect in October, so as I have a RTW in November coming up, I've checked up with the local AC call centre to see if this affects RTW trips.
According to the information the local call centre has received, it appears to be a network wide adjustment and the new 23kg/50lb max weight per bag (still 2 pieces per person) applies to all AC flights, including those as part of a RTW.
Bags weighing between 23kg-32kg will be charged a new flat rate of CAD60.00/USD50.00 worldwide for International flights and CAD35.00/USD30.00 for Canada domestic & flights between Canada -
U.S./Mexico/Alaska/Hawaii.
Bags over 32kg will *not* be carried at all & must be booked as cargo.
Linear measurements remain at 62"/158cm (LxWxD).

One bright spot - according to their info, the *G allowance remains at 3 pieces, albeit at the new weight limits.

From memory CO and NW also recently reduced their bag limits to the same levels, so looks like the start of a new trend, although the Nth Am carriers have always done things a little differently than carriers in other parts of the world. Wonder if this new Nth Am baggage initiative will spread or not?