So why didn't Apple just add Touch ID silently to the Mini 2 like they upgrade MacBook CPUs regularly (Mini 2 "Late 2014").Marketing it as a 'new' model (and raising the price here in Australia) was just cynical.
For anyone who purchases an expensive mechanical wristwatch, you are expected to have it serviced every 5 years. This can often cost $500~800.
Apple could adapt this model where you take your watch in for service after let's say 3 years and get a new CPU, battery and screen.
The biggest difference between a DSLR and phone camera (apart from interchangeable lenses) is control over depth of field (the ability to throw a background out of focus). Two lenses isn't doing to improve this - only a bigger sensor. Perhaps 3D imaging as someone suggested?