The growing prominence of dreaded football agent . . . An option to dispatch a football agent to sign/sell player x.
For example, managing Arsenal. You've tried to sell Ozil, both by offering him to clubs yourself and/or via the DoF. Nope, no takers. You employ an agent to act as an intermediary to sell the player. If successful, the 'downside' would be the agent secures a tasty percentage of the transfer fee.
This could also feed into other aspects for the game. For example, when a team is looking to sign one of your players via an agent - football agent x has been seen with