In iOS native, every picker (when sound is enabled) plays a slightly ticking noise along with the haptic feedback (which is already implemented). This should be added to the CupertinoPicker and CupertinoDatePicker as well.

Edit: also, the upper horizontal line in the focused item looks slightly different than the bottom (maybe the color shade or like 0.5 pixels bigger?) while the native are identical.

[✓] Flutter (Channel unknown, v1.8.0, on Mac OS X 10.14.5 18F132, locale pt-PT)
    • Flutter version 1.8.0 at /Users/miguelruivo/DevTools/flutter
    • Framework revision 2fefa8c731 (4 weeks ago), 2019-07-01 11:33:22 -0700
    • Engine revision 45b66b722e
    • Dart version 2.4.0