SilverWook said:

Perhaps he thought there would be blowback to replacing Sir Alec? (And not just from angry fans.) It would be pretty hard for even Lucasfilm's spin doctors to downplay a headline such as "Oscar winning actor digitally erased from Star Wars film".

The second and third set of SE changes were done somewhat quietly compared to the very much hyped '97 changes.

i always assumed that was why sir alec was left alone. but then anakin should have been left as well, for consistency. why switch it so u have young anakin and old obiwan? makes no sense to me! ;)