1) I would really like to be able to get more involved in the financial part of he club. I imagine it could be done by implementing a new "Chairman-Manager Mode" or something like this. I know that's a difficult thing to implement, but it will add a great amount of depth to the game. Just think about investing yourself into stadium/training facilities etc.
2) I would also like a view from above of the stadium area. This, in connection with the possibility to expand the stadium add bars and pubs, ticket shops and so on would be great (like in Ultimate Soccer Manager series).
3) SI should really think of something to do with the money earned as manager.
4) I would like to be able to create yourself some setplays. It's really something when you see your players scoring from setplay routines created by you.