I did not know this! That is kind of disappointing as I think the open terminal concept is SIN's best asset.
Wow, CX is moving to T4? wow that will be a pain in terms of transiting / changing terminals in SIN..
Due to the growth of budget airlines, the former budget terminal was upgraded, then expanded, before being pulled down so T4 can be built from scratch. And as a replacement of the budget terminal, it seems to be ok as it's designed with check-in, baggage drop, customs, and departure gates automated. Facial recognition technology will also be used. However, it was a little bit too nice, and CX decided to go over there and make it their home. Currently, CX, KA, VN, and the whole AirAsia group are confirmed to operate from T4 when it begins operations.
The problem with T4 is that it loses the benefits and the connectivity of other terminals. Any transfers between T4 and the rest of the airport would require a bus ride. There is no skytrain, and no normal (MRT) train to the city. At this stage, I'm not sure if airside transfer would be possible at all, but we will have to see about that.
They are also building more aircraft stands opposite the road, and a bridge will be built to allow buses to connect from T4 to these stands. While nothing has been said about this, I would not be surprised if they eventually start using these remote stands and have pax bused instead of using aerobridges.
And then, give it another 10 years, T5 should be just about open, and it's going to be one huge terminal. By which time, the 3rd runway, currently used by the military, will be upgraded and connected to the public side for commercial use. The contract for the upgrade was awarded late last year.
Meanwhile in HKG, full practical capacity of the runways will be reached in the next few years, but they still haven't gotten around to building a 3rd runway. There are a lot of people against having it built, and the delays and budget overruns in recent large public infrastructure works are certainly not helping sentiments.