For people used to the iOS passcode lock, the fingerprint scanner
on the iPhone 5S, which Apple calls Touch ID, comes with a
significant drawback: with Touch ID enabled, it’s no longer
possible to set the amount of time since the screen last turned
off before the passcode — or, now, Touch ID — is required to
unlock the device.
So what’s the solution, then? The Require Passcode setting should
be separated from Touch ID. The previous timed options should be
restored, but, true to the setting’s name, the timer should
determine solely whether the passcode keypad appears or whether
the phone unlocks immediately when the user slides to unlock.
Touch ID, meanwhile, should remain operative on the lock screen at
all times, even when sliding to unlock would be sufficient.