Not saying that there is no demand for smaller phones. I'm saying that I would have paid a premium for a 4.3" model in a iPhone 6S body with smaller bezels that included every feature that the iPhone 4.7" model has including 3D Touch/vibrator, screen resolution, better front camera and faster Touch ID; AKA a no compromised iPhone. Not a Frankenstein phone using parts from a 5S, 6 and 6S. The damn phone looks exactly like a 5S.
But as it stands the phone is a good deal if you own a iPhone 6 and below. A current generation iPhone 6S owner would be making a mistake.
A premium 4.3" phone in a 6s body may have been good for you, but not necessarily Apple. Why would they invest in the R&D to create a premium phone that will look like last year's model in 6 months?
And your expectations are somewhat unreasonable as well. Are you an engineer? Otherwise, what makes you think Apple could make even a 4.3" model with 100% of the features and performance of the 4.7" 6s, without any compromise? If such a thing were possible, shouldn't the 6s have the same optical image stabilization camera as the 6s Plus? And equivalent battery life? Not everything can be miniaturized to solve space limitations, which means compromises have to be made. Do you really think Apple wanted the camera budge sticking out of the iPhone 6 series phones?