That means getting rid of the home button, so a redesign would be needed. Apple doesn't do that on -s devices.New iPhone needs a larger screen to ratio estate, the top and bottom bezel space is way to wide and ugly.
IPhone 6 not even in the top 30.
http://www.phonearena.com/news/The-...agships-relative-to-their-screen-size_id54487
With the rumored Force Touch hardware going to iDevices though it could mean that the home button becomes obsolete and you return home simply by using a Force Touch gesture. Allows for Apple to get rid of the huge chin.