Tried a Galaxy S2 in the shop today. It is not that thin! I was expecting a lot thinner from what people said! It would have been a perfect size for most people with a 4inch screen in my opinion.
It really is thin. The size makes it appear thinner, certainly, but it's still extremely thin nonetheless. Were you expecting it to be like paper or something? I can't see how they could have made it much thinner to be honest.