CGI renditions of actual people

In the case of say Ewan McGregor taking up the role of a young Obi-Wan Kenobi, a character first assayed as an older man by the late Alec Guinness, I would contend that this should, and I suspect will, remain the norm in most cases. For something like Martin Scorsese's "The Irishman", digital de-aging is deployed to maintain continuity with the performances across the entirety of a single film. A film which uses the technology the way make-up has been used for centuries to make actors appear to be a different age (most often older) than they actually are. Much as something like "Once Upon A Time in America" (to use another DeNiro starer as an example) wants us to be aware of the young man nested somewhere inside the old man DeNiro has been made up to look like in the 60s sections of that movie, "The Irishman" wants us to be aware of the old men lurking inside the skins of younger men during its earlier set sections. In that sense, the movie is less interested in convincing us that Robert DeNiro or Al Pacino have aged backwards 30 years, than it is in creating a sufficient level of verisimilitude that allows the story to be told with the same actors throughout. Variants of this approach have shown up in any number of Marvel movies.

Of course, "Rogue One" recreated Peter Cushing as a digital character, which was then mapped onto a new actor performing the role, creating an array of opinions about "raising the dead". Many of which feel valid.

What's been seen recently however, in the case of Luke Skywalker in "The Book of Boba Fett", is something different. In that instance we're dealing with a mix of Mark Hamill's voice acting, and a "performance artist", to physically assay the role, who has a mask of Hamill's face (known as a "deep fake") digitally mapped onto his. This though is not technically a CGI rendition of Hamill, but rather the merging of the performances of two human actors with computer technology. Since Hamill's involved and the effect is quite convincing, I take no issue with it. Were it Carrie Fisher however, who is no longer able to give her side of any new performance of Leia (younger or otherwise), I might be more hesitant. Though, I don't know that I'm rigidly opposed.

But, why not simply recast the role? Well, because, unlike Obi-Wan in the prequels, it has been established Mark Hamill, circa "Return of the Jedi", is what Luke looks like at the age he is in "The Book of Boba Fett". That frustrates any possibility of recasting, on the belief that audiences would not accept it. In the past, where the technology was not available to "de-age" Hamill, the Luke character would simply not have been featured. It's not like "Bond" where the series can be rebuilt around a new actor. "Star Wars" is expected to remain internally consistent in a way "Bond" isn't.