I believe that feature-wise OS X 10.10 and iOS 8 are quite nice. Apple really should adapt something like Intel's tick-tock strategy. Release iOS 8 with new features at 2014. Release iOS 8S with all bugs fixed in 2015. Release iOS 9 with new features at 2016 but allow customers to downgrade to iOS 8S if they want to, for at least a year. They'll have to support 2 iOS versions, but people will have a choice between new features and stability.