Morally, it's the right decision.
But the PL have made a rod for their own backs here surely?
Fail to deliver a proportionate punishment to Man City and co., they'll be deservedly accused of rank hypocrisy. Then Everton could be the ones doing the suing.
Punish those teams proportionately through relegation or title stripping or the like (as they should, based on their own rules), they'll be devaluing their brand and/or encouraging those teams to turn around and stick two fingers up saying "we're off to the super league".
Just one of the reasons why the FFP rules are an unworkable joke.