The upcoming iPhone 6s will reportedly borrow more from the Apple Watch than Force Touch. Apple is reportedly looking at adding a new set of animated wallpapers to its next iPhone, along the lines of the "Motion" faces on the watch. Those faces include blooming flower and jellyfish.
The new wallpapers on the iPhone 6s are said to include animated fish and multi-colored smoke, according to 9to5Mac:
For the new iPhone, we are told the types of motion wallpapers range from sets of animated fish from a koi pond to colorful arrays of smoke. In recent iOS 9 betas, Apple added new colorful wallpapers including colored smoke against a solid black background, and the same effect is likely to be fully animated on the iPhone 6S.
While this feature could ultimately be cut from the launch of the new phones, it should be noted that animated wallpapers have been included in iOS since the release of iOS 7. It makes sense that Apple would eventually want to expand what it offers in that section.
As noted around the time of the Apple Watch's release, Apple takes many thousands of photographs to create the Motion faces for the watch, rather than relying on CGI. It's likely that they'd use similar techniques to create backgrounds for the new phones.