Why do we not have an INTERCHANGE & SUB rule setup for UMPIRES?

The AFL football operations person said we needed a sub rule because it was unfair that one club can overuse the interchange, while the opposing club may have players out of the game injured, and that he considered unfair. Coach's can rest players on the interchange, who are playing poorly or who have made an error, which may have cost the team a goal,they are held accountable for their actions . The AFL are trying hard to turn the game into a circus,and while their umpires can control the outcome and end result of games,i ask why not also hold umpires accountable for mistakes during games,and interchange rest or sub them off as required like players. An umpire was obviously tricked into paying a free in saturdays game to Geelong resulting in a goal. The Geelong player openly admitted next morning, even thinking it was funny that he "milked a free from his young Essendon opponnent ".That umpire needed be removed from the game immediately, or subed out for his total incompetence,and for good measure drug tested . That umpiring decision could have cost the Bombers the game, and that also Mister operations manager is wrong unfair, and incomprehensable ! The competitive nature and professionalism of todays game allows coach's to take players from the ground and explain mistakes by instant replay on computer. Why not use the same technolodgy to explain umpiring mistakes during a game. Yes i know some smarty will say the game will be delayed too long while all their mistakes are discussed, however in all seriousness updating the professionalism of umpires is paramount. Umpires conned into paying frees like the Essendon incident resulting in a goal is in simple terms cheating. If i was umpires boss i would insist umpires never again pay frees to that Geelong player again. If it eventually puts the player out the game so be it. The AFL need to fair in making the game fair for all , and start by making umpires full time instead of part time as they are now?

NB: Yes,if you are wondering, I am sick of the AFL circus and the clowns that run it !