I believe it's because lot of people really thought at one point that next-gen will be quite weak when it comes to "power". Now, when PS4 specs are more or less known, it seems that faith is restored that what's coming will really be a big leap, and since it seems that PS4 is one with most "power" it gets most hype.
Despite what's most important in gaming (gameplay), people will always want to be awed by new visuals...







