I expected the NFL to surprise people with how hard they came down on this, but was even then surprised how strong these measure are.
I do think they're reasonable and proportionate. Having had a quick glance at the findings, it seems a large part of the penalty size is because of:
'a deliberate effort to conceal the program’s existence from league investigators, and a clear determination to maintain the program despite express direction from Saints ownership that it stop as well as ongoing inquiries from the league office.'