Team Emblem Creator
Right now, you can't convey your team's personality with the current icons, and they look more like user icons than a team emblem.
If we had a editor that allowed us to drag and drop common shapes of different colors and add letters, team emblems would be unique and recognizable.
Think about the Logo Creator of the Pro Evolution Soccer games. And I'm sure there would be more ways to monetize this feature (e.g. selling unique shapes, exclusive colors).