Lots of people clearly hate Roseman. They hated Banner, too, but if you followed his interviews on the athletic you can see he was really smart about football--I think the haters were wrong.
If one has loyalty to Pederson for the Super Bowl, Roseman deserves some, too. He built the roster, signed Foles and other helpful free agents, etc.
In terms of looking at things that were on Pederson without much influence from Roseman, I remember off the top of my head:
• Wentz turning into a bad HS QB this year (might be on Wentz, too, but Roseman had nothing to do with it)
• Keeping Mailata on the bench for lesser players; not recognizing he was good until they had to play him.
• Benching Fulgham for Alshon; not recognizing Fulgham was decent before being forced to play him
• Playing Pryor ahead of Herbig
• Mis-managing Lane Johnson's injury (medical staff might be partially culpable, too)
• Ertz falling off a cliff.
• What appears to be a bad audible structure (did not work for Hurts, either) kill, kill, kill
• A passing game that the talking heads who do all-22 reviews say does not scheme receivers open (Cosell, Duffy)
• A poorly disciplined team in terms of overall penalties and dead ball penalties in particular
There are probably more. This doesn't exonerate Howie, but it's certainly a lot of things that at least appear to be Doug's fault.