Everyone that is a star war fan will love what I'm going say. Its about this big picture of Qui gon Gin. Lets say Obi wan Kanobi died instead of Qui gon Gin, Qui gon Gin was very wise and was the 3rd best jedi at the time. He had magnificent feel for the force, imagine if Anakin got that qualities. Anakin wouldn't have the dream about the loss of Padimea (which she was grown up when he was a kid and they got married, she is WAY to old for him). It would have also stopped him from the temptations of Emperor Palpatine.
Was Obi wan a bad trainer? He didn't get full jedi training because of the loss of Qui gon Gin. Also Obi wan seemed to have a less friendlier and less confidant personality, that made Anakin get mad at his teacher which made Palpatine mor tempting. Now movies 4-6. sould we immediately train Luke? Naaah, lets wait until last freaking second and nearly loose(Luke also could have saved Obi wan from DEATH!). Yea, Star wars could have been shorter if stupid Darth Maul didn't have to kill Qui gon Gin.
