We at OpenLieroX actually tried to solve this for game settings. OLX is a 2D shooter-like game. In the game settings dialog, for each setting which was changed

We at OpenLieroX actually tried to solve this for game settings. OLX is a 2D shooter-like game. In the game settings dialog, for each setting which was changed by the user, it shows a 'reset' button next to it. Also there is a way to just show the changed settings. You can also filter the settings by how advanced you want to go (a bit similar like in VLC but with more levels). And when you hover one setting, there is a comment section below the dialog which describes the setting.