Pretty straight forward suggestion. It would be nice to have access to how much your player has improved since you bought him. Something like a graph showing you his average percentage in Def, Att and Phy over time.

Additionally some stuff could be added to the graph like red horizontal lines of inactivity showing periods of being injured, thus being able to assess if a player is injury-prone.

Why this would be useful is to know which players are slowing down in development and whether or not to sell them soon. It would also be useful in knowing which players to focus on training.