We simply can not criticize the umpire's alone, because now a days the umpires are put under tremendous pressure by the television replay's, media's and by the players.
If a batsman knows very well that he has nicked the ball, he should walk straight away and should make the umpire job more easier or Sometimes when the ball pitched on the leg side he should not appeal. If he fails to do so, the player should be banned for some matches and that ban should be decide by the current touring opposite team (The opposite team can make that player sit out during the important matches).
Also the third or the fourth umpires also should intervene when the field umpires go wrong with the decisions.
