A 6% increase is fair if you look at it the following way:
If the average price of a season ticket at city is £400, (the average price may be even less) a 6% increase would only be an extra £24.
If rounded up to an extra £25, not £24, and times by 40,000 season ticket holders, that is only £1 million extra for city.
Considering Sheik Mansour has spent millions on players and we are watching some of the best football seen at man city, we should be happy that our season tickets are still a fair price. That saying though, they may increase them by more than 6%.