That ending is stupid. What's the point of all that time travel to save John Connor if he's just gonna get killed and have a machine take his place. What's the point of making Marcus look like him anyway. How many people actually see Connor? Then the other ending you see on Maximum movie mode is more stupid. After they make Marcus look like John, he kills everyone, including Kyle Reese, totally destroying past Terminator film events. The ending they went with is just more Logical than these darker but insane endings. Marcus gets his second chance and completes his arc of redemption and claims his humanity, and John gets to live on and take his place as leader of the resistance.