Solving Existing Problem verses Innovation (ios 10 Lock Screen)

previous ios lock screen

slide to unlock

ios10 lock screen

either use TouchID or press home button to unlock

Apple changed its lock screen in ios 10. They introduced the new way of unlocking screen using TouchID which recognizes users' fingerprint or unlocking by pressing home button.

The old way "slide to unlock" is a brilliant design. User knows how to use the old way to unlock screen immediately after they read "slide to unlock". It doesn't require users to learn (Usability: efficient and learnable). Too bad that they abandoned the old way of unlocking screen. 

The new way "press home button to unlock" sharply increases the chance of using home button. Lots of iphone users encounter the problem of broken home button. As an iphone user, I avoid unnecessary use of home button at all cost even though sometimes it takes me some more operations on touch screen. Also, the new update brought me confusion at first and I need to learn how to use the new unlock (Usability: not satisfying). 

The fingerprint technique, TouchID is not mature enough. I fail to unlock using TouchID to unlock when there is sweat on my hand, which happens to me a lot (Usability: not effective and not satisfying). 

I can see that Apple tries really hard to introduce TouchID unlock. My own guess for the reason they changed "slide to unlock" to "press home button to unlock" is because of TouchID. When using TouchID, users put one of their fingers on home button, and they want both operations on the same place, so they changed "slide to unlock", an operation done on touch screen to "press home button to unlock" an operation done on home button.

Based on UCD, designers should do research on users' needs and design solutions. Personally, my need on avoiding broken home button is much stronger than on TouchID and I prefer "slide to unlock". To me, TouchID for screen unlock is not something necessary. The update to ios10 did not solve my problem but increases struggle.

Designers should focus more on solving the existing problem instead of innovation.