3.5 inch screen was amazing for 2007, it's time to move on.
Not at all. 3.5 inch screen works great for many users, and I for one don't want it to be bigger. I like my phone the size it is, which allows it to fit nicely in my pocket. I don't want to have to wear cargo pants to be able to keep it in a pocket.
Some people out there (maybe you) truly want a bigger screen/device to make it more usable for certain tasks. But I would bet that the majority of people crying for a 4 inch screen are doing so because they worship tech specs and want to brag that their phone is better than their friend's phone. For those people, they just need to go get an iPad. Most of us want to keep the 3.5 inch screen.