What the hell happened to waiting to release stuff because "Details matter"? I know Apple wasn't perfect under Jobs but it wasn't this bad. The company seems too lax.
iOS releases under Jobs were much more iterational -- a few new APIs, some skeuomorphic doodads, that's about it. But under Cook, technical advancement has vastly increased in pace not only with iOS, but also ancillary systems it touches (iCloud, Apple Pay, Touch ID).
Doing while keeping to a yearly release schedule is IMO causing these software quality issues. The software engineers simply don't have enough time to work all the bugs out. I think Apple should move to a two-year iOS schedule, because I don't know what else can solve it but time. Throwing more engineers at a problem only helps to a certain point.