A (decent) equalizer.
Logarithmic volume control (So that the volume doesn’t jump from 0 to 50 when trying to listen in quiet environments)
ID3 tag editor.
Would default to directory based navigation, ID3 tags optional.
Actual file management system where I can actually see and move the files around as I wish.
Ability to play music files from the phone’s memory when connected to a computer.
CODECs should be handled at the OS level, (What do you mean insert_app_here won’t play wav files?)
A reliable standard for lockscreen music controls.
Drag and drop playlist creation.
That should do it.
