Sadly people that prefer smaller phones are now part of the minority. Do you really think that everyone who bought a 5s bought it because of the small size? I believe a huge number of people bought it just to stay in the ecosystem and their waiting for a larger display.
The only way to satisfy everyone is to release multiple sizes. There is no one size fits all.
That is my hope...they keep multiple sizes. The moto x is a very small 4.7" phone, so that or smaller works. Granted a lot of the reason the moto x feels so good in hand is the form. I doubt apple will have a curved back.