A lot of people are talking about a one off points deduction. For me, this would fall way short of what is deserved. We are talking about sustained cheating over many years... if the punishment only affects them for one or two seasons it's a very small price to pay with great rewards for City.
The punishment has to be relative to the crime. We are taking about sustained cheating over years, the punishment should be such that you will stop other clubs including City from trying to do this again.
It needs to be a long term painful punishment, I am talking several seasons of deductions and transfer bans. If it is limited to only one or two seasons, they win.