Back in the day apple didn't really cave to pressure. I believe their process was like they say it is. Make the best phone they can and release it hoping people will dig it.
But now with the 4inch screen, ios7 being a huge departure from what Steve jobs would've done and the iPad mini, I think the company is slowing changing to react better to what the market wants. I think they're approaching this slowly and it started with the iPhone 5's screen increase. Now that we are on the s version, gotta keep it the same. But, and I'm pulling this prediction out of my ass, the iPhone 6 will be similar in overall design to the iPhone 5 but with a larger screen. If I had to guess, it would be 4.5 to not scare their base too much with the idea of iPhone going into phablet territory.
Come back in 12 months to see if this prediction came true.