I know this is an old one, but it is worth repeating and it is the only thing that has truly niggled me so far.
Whenever I give opposition instructions it is related to the position that the player players. If he swaps position then in effect my tactics are changed and the whole shape of my team changes. This invariably ends up with my players over focussing on one area of the pitch an neglecting another.
Ultimately this results in goals against that are created by the interface and not my tactics (however inept they may have been in the first place!).
At the very least the instruction needs to stay with the player, but even better would be a tick box to give me the choice. At least give me the option of losing by my own mistakes.
And yes, I am bitter because I have just conceded two goals because of swapping positions.