I would have to imagine that the newer 747-8 would have the much lower pressurization and other comfort standards of its generation of aircraft in the 2000s; the problem is that it didn't really sell so most people did not get to fly in one.
Two small corrections:
1) If it would have had a change in internal pressurization, the -8 would have a higher pressurization to allow for a lower cabin altitude pressure.
2) The -8 does not have a higher pressurization, because they did not change the fuselage construction. Newer airplanes have lower cabin-altitudes thanks to the use of composite materials, allowing for better fatigue properties.
This is actually because the -8 wing is MORE efficient than yhe -400. There is a regulation that in case of a pressurization failure the airplane has to be able to descend below 15,000 feet in a certain time. The -8 wing has less drag, so it is easier to overspeed in descent, and they had to limit the maximum operation altitude to compensate.
Not always. 777X uses a conventional fuselage but has a 6,000 foot cabin compared to the 8,000 foot cabin on the legacy 777.