The unfinished feeling in iOS 11 mostly comes from UI and animation. UI elements in iOS are quite inconsistent, mixing a variety of UI elements, which might look quite similar but introduce a disconnected feeling for UX. The inconsistency of those elements majorly stems from those UI element updated in iOS 11, such as Large Title and new Search Bar. In my opinion, those newly introduced elements, which might be unfamiliar and new even to Apple engineers, have caused many inconsistent UI experience in iOS 11.
Many of you will look at this and consider it a bunch of whiny nonsense, but the problem with Apple being lax on details is that it turns into a case of monkey see, monkey do. Third party developers will become lax as well, leading to an overall degradation of UI quality and consistency. This is the last thing iOS, which has never exactly been a visually consistent operating system to begin with, needs.
People go nuts because the ports on the bottom of a Samsung phone – which you effectively never look at – aren’t aligned, yet, ever since iOS 7, Apple has basically been winging its iOS UI design and polish.
Something about grading on a curve.