There is such a thing as "too thin" you know...
I have a GS3. It's too thin. It's too thin to feel good in my hand, too thin to have a rounded (palm fitting) back, and most importantly to me, have a giant battery. If it was 1.5 or even 2 mm thicker, the battery could have easily been 3000mah like the note's, and it would have been nicer to hold.
Unfortunately, Samsung is going to make the same mistake again on March 14th, when they show the world that the S4 is EVEN thinner.
That said, I probably still will buy one, because I'm sure they would have figured out how to improve battery efficiency with whatever processor it ends up having, fit a bigger battery, and since the back is removable, I can get a larger, thicker, third party battery if I want.
I just wish they cared more about "It fits your hand better" instead of "LOOK! ITS THINNER THAN THE IPHONE!" because that is not necessarily a good thing. I think HTC has the right idea with the One, but obviously at the cost of switching the battery and adding cheaper memory. Phones need to become a litter thicker and rounder again. For palm's sake.