IMO, a bigger screen is welcome.
I believe that people have 2 'worries': 1) form factor and 2) one handed use (how ridiculous)
Form factor: how big the device is with everything included. People on this site are talking about not being able to fit a 4.7" iPhone in their pocket....are you serious? A 4.7" screen, we're not talking about an iPad mini form factor increase...I mean, come on! The device will be bigger, yes, but not to the point where it'll stop fitting in your pocket and end your whole life (that's how dramatic people on here are)
One handed use: a .7" jump is not THAT much. Think of the iPhone 4 to the iPhone 5 screen and add a little more. I don't understand why people NEED to use their device one handed. It leaves me to wonder what they're doing with the other hand that is SOO important that they NEED one handed usability or it's a deal breaker. Practice your hand shimmy to shuffle the phone around. I've sure mastered it but I can comfortably use my iPhone 4 (3.5") and iPod touch 5G (4") with 2 hands.
People talk about not wanting it, but I'm sure that one of them is going to be ordering the phone or standing in line at launch day, that's written in stone.
Be more open to changes on the phone. Apple needs to change as the needs of people and the market change. If it's a deal breaker, get yourself an iPhone 5S and hang on to it, it's future proof for a few more years.