There's probably an argument to be made that 5A is better than 6A in the WPIAL. Outside of Pine-Richland, NA, and PCC, none of the 6A schools have been particularly competitive in decades in the WPIAL, while most of the districts longtime powers dropped to 5A in the classification switch. Sure PR won't play North Allegheny and PCC, but picking up Gateway, Woodland Hills, McKeesport, Penn Hills, Penn Trafford, Peters Township, Upper St. Clair, Bethel Park, plus South Fayette/Thomas Jefferson if there is movement up adds a bunch of really good programs to their class.
And I'm not sure why there'd be pressure on them to play up. I guess Aliquippa does it and Bethlehem Catholic elected up two classes in that 1998-2002 run, but it hasn't exactly been the expectation for top tier teams in lower classes. It's not like there's been an outcry that Archbishop Wood or Gateway didn't move up from 5A to 6A.