Is it a fair comment that CAS will review UEFA's case to determine that it's within the UEFA process regs, that it has evidence to support the conclusion and that the punishment is fair? After that, it's down to City to counter that evidence.
As you say, the current situation is 'guilty'.
UEFA have found x, City say it is wrong because of y,z and a and even if UEFA are right the sanction is disproportionate.
UEFA say, no it is right because of b, c and d. And UEFA say the sanction is not disproportionate and that CAS have no power to change it anyway.
CAS decide.