The most wanted feature for heavy players is definetly more historical statistics.
Dear Nordeus, this could be a killer feature that open plenty of interactions, sharing data, discussions in the forums,... to your users.

I understand that there could be manyIT issues, storing so many data so the suggestion I give you is to implement a simple export option in txt, xls, ... or whatever you want of the current statistic table.

The "nerd" players as I am for instance will be happy to download the data every end of season to keep history of my team.
The further options is to keep for the season also sold players.

Thanks and sorry if I repeat something already proposed.
Cayembe