Yes, that was the message of Steve Jobs back in 2010, referring to the 3.5" screen as the "sweetspot" for smartphone screens. Apparently, he was wrong with his first statement, but I still do agree on the latter. The 3.5" screen on the iPhone was the only display my fingers could reach every single pixel on without too much discomfort. That is no longer true for the 4" screen on my current iPhone 5. I regularly have to move the phone up and down in my palm which is quite an awkward thing to do. Though I have to say I do not have the largest hands. And I am not sure I would want to handle a 4.7" or even 5.5" screen every single day.
Of course we'll get new models each for testing purposes anyway. Curious to see how I will think about the new sizes in a couple of weeks.