The problem with using Sebastian Shaw’s force ghost in ROTJ is also that he wasn’t blond like Hayden and had rounder facial features.

Ok, his ghost has grey-ish hair but it’s still obvious that Shaw must have had quite dark brown hair when he was younger. Hayden and Jake Lloyd were both blond though (probably to make Anakin look similar to Mark Hamill / Luke). They were pretty bad casting choices when you compare them to Ewan McGregor as younger version of Guinness’ Obi-Wan.

Maybe it would have worked better if Anakin was the dark-haired one (like Leia) and Padme had blonde hair (like Luke).