The Gloomy Face Mod replaces the face texture for all pawns with these anime inspired faces.
This mod is compatible with existing saves, it does not require you to start a new game.
Gloomy Face Mod Review
If you wish your pawns were more expressive, or they simply had better faces, the Gloomy Face Mod is probably what you've been looking for. These anime style faces will certainly lighten up the mood in the rim.