i dont agree with killing off a character such as this. main characters should only die in movies if they dont reach trilogy-length
itd be like killing off John McClane, or Rambo, Jack Sparrow, etc. it would just be incredibly disappointing for the viewers.
now, it wouldnt such a terrible idea for Indie to assume the role that his own father played in one of the previous films. accompanying Mutt on an adventure as more of a sideseat character.
but obviously, the best choice would just be for Harrison to be the actual star, the way he has been this whole time. Spielberg and Lucas have pissed off their consumers enough over the years. they DONT need to do it anymore