Custom icons or changeable system notifications like battery, signal icons etc. Colorful and replaceable icons make more interesting than those boring dull mono icons
Realtime weather wallpaper..Why not know about the weather in my location just by glancing at the screen instead of going and opening an app?
Colored battery levels. Green if it is above 50%, Yellow if it is above 10% and less than 50% and red color if less than 10%. This color coding is already available in my 14 year old Sony Ericsson phone. Why not in my favourite samsung phone?
Choice of choosing stock apps while configuring the phone. Such an option will help users choose only the apps they are interested to use.
Include a hardware section in the About phone. This helps in quickly finding out what is the phone hardware.
Date and Time imprint on photos. Provide an option to imprint Date and time on photos when a photo is taken using camera. Not through a sticker.
Themes for messages app. Why not more themes for messages app? Why not the image or logo of the sender against the message?