I went and played with a note2 the other day and with the phone in my palm I can get my thumb 1/2" from my ring finger in front of the phone. Like I said, I have pretty big hands.
Like everything else, they made a big phone that sold a lot so they'll keep making them bigger and bigger until they quit selling. I want to say though that 6" is about the perfect size for a phone screen. Any bigger than that and they're really in tablet territory.