I don't have an iPhone, but I prefer smaller screens, so if I did use iPhones, I would have preferred they kept the size smaller.
I'm not one of these people that uses my phone as an entertainment center. I don't see the pleasure of watching movies or playing games on a tiny screen. Screens are slowly getting larger each year, but still, we're talking about an average size of 5" on these things. For entertainment purposes, that's ridiculously small and pointless. Therefore, IMO, the phone should be as small as possible, used for calls, texts, and the occasional internet search or maps.