I have never purchased the pro football game here but I am considering the next version when it is released. I apologize if my suggestion is already a feature of the game.
One problem I have always had with professional sports games is the inability to offer creative contracts to players. Every game I have played, if a player wants $100 million over five years, the only way the game allows me to pay that is a level 20 million per year. I would like to see a game that allows some creativity. For example, lets say this player request is coming from a 33 year-old Pro-Bowler and future HOF player. In that case, I might decide that the best way to meet his demand is to offer years 1 and 2 at 30 million each, year 3 at 20 million, and years 4 and 5 at 10 million each. This still reaches his stated overall value but allows me to free up cap space for other stars as he ages and his skills decline.
In a perfect world the option of offering incentive clauses would also be programmed in but I know this might be impractical from a game programming perspective.