silverwheel said:

It ruined one of the most powerful lessons of the series. The ghost of Old Anakin symbolized that while he could not undo the many terrible things he had done, he could still make amends and seek forgiveness. Old Anakin symbolized a wasted lifetime. Hayden's ghost basically gives the character a free pass. Plus, Old Anakin fits with what we had just seen in the movie - a tired old man trapped in an iron lung, desperately wanting to get out. Now, in death, he has his release. The notion that his ghost can just "go back" makes no sense, literally or metaphorically.

This. Would somebody buy this guy a beer?

EDIT- Oh, one other thing. I used to be fairly onboard with the special editions. I felt like there was some merit in altering the trilogy. Ghost Hayden was the first step in me seeing the error of my ways.