In many respects I consider the new units to be a downgrade, mainly half length, not gangwayed throughout, hard seats, not many table seats, and no buffet, but at least Pullman dining has survived.
And right on cue, here's some repetitive knocking of IETs...
GWR had 53 HST rakes at peak fleet size. It is getting 35 nine-car Class 800s and 802s, ie long IETs are direct one-for-one replacements for two-thirds of the HST fleet.
The IETs are not just replacing HSTs, they are replacing five 180s (and would likely have been replacing more than five if GWR had been able to get its hands on more 180s when it took them back in 2012) and three-car Turbos on a number of Cotswold, Oxford and Bedwyn diagrams, where a nine-coach 650-seat train would be an utterly inappropriate, over-the-top replacement.
The five-car sets are also allowing developments such as an hourly through service in both directions between London, Gloucester and Cheltenham and new services like the off-peak limited-stop Bristol runs - again situations where nine-car trains would be capacity overkill most of the day.
Not forgetting the likely reintroduction of portion working on a number of express services west of Plymouth - something that was an established fact of life until fixed-formation HSTs appeared in the West Country - even in ye olden glory days of multiple restaurant car services, most of which, I'll warrant, dropped their kitchen-buffet cars at Plymouth, or picked them up there.
But why bother with all those new services, or commonsense use of resources in peak and off-peak periods or on quiet sections of journeys, when you can just run long rakes of half-empty coaches up and down all day to the existing timetable instead...?
Seat comfort is s matter of individual opinion - as this forum continues to prove on an almost daily basis.