Red Cards

I have seen so many football matches where it has been spoiled as a competitive game because a player is red carded.  The player is obviously punished but then so are the fans, should not this law not be reviewed and a substitute allowed and thus not spoil the match for the fans?  The punishment for the players red carded should be made harsh, after all a manager who loses a player for say 3 matches instead of one is not going to be pleased?