From looking at the top 30 players by value in the world (which would indicate 30 best players in the world) there are only 2 players who are below the age of 30. This is completely unrealistic. It takes far too long for a player to gain balls at a young age. With the only deterioration being -2 balls in speed and stamina the game is heavily focussed on players in their 30s and it is nothing but luck on when they will retire.
I would like to see the best players in the world being in their late 20s and more variation on how players deteriorate eg Ryan Giggs vs Brazilian Ronaldo