I really hope an RGB screen makes it into the S4. I almost bought the S3, but the nasty plastic and green/blue whites prevented me from doing so. Likewise, the small storage of Android phones isn't very appealing. I'd rather have 32Gb as the starting point and either have it expandable or give options for larger internal capacities.
To make this perfect, they will need to have the following:
Quad-core processor with Snapdragon S4 Pro speeds or higher
2gb or more of RAM.
5" 1080p RGB display with a THIN BEZEL.
Physical dimensions no larger than current S3.
Higher quality optics, no necessarily more megapixels.
F/2.0 apature.
Faster, more reliable auto-focus.
Dedicated camera button.
Metal/Glass construction.