Also, the plans I have seen here and elsewhere don’t suggest there is going to be 25% less seating.
Frankly, it is probably a better compromise than what the poor buggers in Perth have to put up with, where all A-series and some B-series trains contain 100% longtitudinal seating. That must be fantastic for passenger comfort if you happen to be going across town on a Yanchep-Mandurah trip.