What was the aircraft swapped from? You're wrong about PE on CA's A350 at least - it is very much a different product. Cabin layout is 2-4-2 (vs 3-3-3 in Y), seats are wider, have more storage, leg-rest etc. When I flew PE on the A350, I got 4 choices of main course for dinner, the hot dish was on a china plate, I got a pre-departure beverage, a hot towel, a bottle of water at my seat, better headphones and slippers.
I'm not sure what aircraft they had booked on, but I very much agree that bulkhead Y on an A330 is a material downgrade from PE on an A350.
That said, the correct course of action would be to take it up with customer services afterwards, rather than complain about it on board. (Although I'm in the process of that after my own downgrade due to involuntary re-route, and haven't got very far yet...)