Yes will have no sky train connecting. Don't know if there will be an airside bus-transfer system.
I didn't know though that the arriving / departing passengers will be segregated. If that was the case, it is highly unlikely that you will have airside access to other terminals (i.e. presumably an airside bus transfer system will be as follows T4 arrivals => T1/2/3 airside =>T4 departures)
What will be interesting is if there was an airside bus transfer, whether you can use your CX T4 OLCI boarding pass to clear immigration / security at T 1/2/3. Still doesn't help if you have checked in baggage
At least CX will build a new lounge there!