I personally think we should be able to set any price on a player we want to sell - including letting the player go for free (Note that isn't sacking him - but letting him transfer for free).
After all, in RL players move for free all the time in the middle of contracts when it works out in both the club and players interest.
The fee due to be paid to sack players is too harsh. Even a mutual termination offer where the player would take a cut of what his contract is worth would be better than now.