Given that they are starting to repaint the 330's, it would appear they will be staying in the fleet for a while. At $50 oil, the 330 is a very competitive aircraft for transatlantic missions.

My understanding is that AC intends to use the 330's and 767's as "flex" capacity - as the rest of the 789's arrive these are cheap aircraft that have been bought and paid for that they can use when it's busy and park if the economy slows.

The 333's are on average 17 years old, on the older side for A330's but still 10 years younger than the 767's that remain in the AC fleet. That might given you some indication.