To be able to design your own stadium, like in LMA manager.
Also to be able to sign your own sponsor for kits and stuff? Maybe to be able to change the colour of your away kit every other season.
Agree with this one, designing own stadium and looking for own sponsor and kit editing. I also suggest adding the manager's personal life, like marriage, personal sponsor, etc. That will make live as a manager completely, not only on the field. I know the latter would be a hard one.