This has probably been mentiond but I would like the chance for when you buy a new player he is unvieled as an official player such as Ronaldo did at Real.
My sunday league manager also gives the referee a personal mark out of 10, maybe this can be introduced into the game as I'm sure real managers give a mark out of 10 for referees?
Although you may not be able to have real life sponsors, maybe you could have certain sponsers and they are visible on your team jersey.
Fifa games also have such questions which says things like "So and so, or a few players have been asked to attend a charity event, do you let them go?" Things like that.
More realistic transfers.. although City are ruining the transfer world, It's nice to be realistic on them for example If I wanted to buy someone I wouldn't want to have to pay an unrealistic price when he should be bought for around a much lower sum.
I would like on the editor to be able to pick your design of stadium. For example what the look of it would be, what colours the seats would be.
Another great feature I think would be if you can see your team walking out the tunnel in a line by the side of the other team.