A good number of flights this spring were forced to be operated 3 man against RPs. So the notion of a phased and planned introduction of 3 man Europe flights is a joke. I can guarantee that flights will operate 3 man willy-nilly as they run out of crew and have to cobble together a plan. That's one of the things that has to be considered when comparing CX with other airlines. A stable roster with a solid rest and recovery plan is one thing, CX's rostering mess adds another dimension entirely.
The potential for delays and cancellations is also high. With 4 man ops the FDP is 18hrs and the crew get on and divide up the rest in some sensible fashion. Not so with 3 man ops. It's not a case of 3 pilots, 15hr FDP, and get on with it. A basic FDP has to be extended by inflight rest. If the required FDP is 14hr30 and all three pilits have a basic FDP available of 13hrs, all well and good. A small delay can be accomodated and remain legal. Throw in some roster disruption with one crew member turning up with a basic FDP of 11hrs or 11hr30 and life starts to get complicated, tiring, and very soon illegal. One pilot may need 6hrs rest, another 3hrs, and the third may have to be burned out to achieve this. The potential for extreme fatigue is high, especially for those FOs who find themselves being burned out.
I don't want 3 man long range ops as I'm concerned it might kill me. However, I can see how it may be workable if there is the flexibility to have a sensible rest plan, the roster is stable, and there is decent recovery period (5/4/3?). Unfortunately CX doesn't do sensible, stable or decent.