What was George Lucas' reasoning for changing Anakin's head?
At the end of "Return of the Jedi" Anakin's head was replaced with the head of Hayden Christensen.
This question asks when this was done, but what were Lucas' reasons for doing this? All of the original Star Wars fans would surely be disappointed (as they were).
There is indeed proof that only the head on the ghost was changed, which makes it all the more ridiculous.
It seems that every time they release Star Wars on a new media they change something. Why doesn’t it stay the same?
Why did he make a lot of changes? Because he can and he thought it would be better.
You commented "all the original Star Wars fans would surely be disappointed", so it is worth mentioning that Lucas has explicitly described his reasoning here: as he views it, all the original versions will be lost, destroyed, and forgotten. He believes that his definitive legacy lies in the Special Editions and with children who are watching the movies now for the first time. He wants to connect these young first-time viewers to the old movies, and he believes he can do that by editing the original trilogy to look more like the new trilogy.
Lucas had repeatedly stated that he has an artistic vision and all the changes are to make sure the movies are as close to it as he wishes. That's the one and only reason.
As far as Anakin's head, that one actually made sense. Darth Vader wasn't a Jedi, so it was pre-Darth Anakin's shape that would be the most natural for a Jedi's Force Ghost. That is how Anakin remembers/sees himself.
P.S. The following reasoning is listed on Yahoo Answers but I haven't found proper sourcing quote so it's suspect:
First, Lucas was trying to establish a "familiar face" to the character that would link the OT and the prequels together. If he had stopped there most "old school" fans would have still not liked it but would have let it slide ... BUT ... his second reason is asinine. He said that a Jedi's "Force Ghost" is the image the Jedi had of themselves when they died and that Anakin died when he became Darth Vader.
why should the Force-Ghost-ability be restricted to Jedis? Is this canon-information?
@TillB - I believe so but I haven't yet read the relevant couple of works so my info is from Wikia.