Eh, I don't think this is an option that should be pursued quite THAT vigorously.
Digitally reconstructing actors as they once were - whether dead or still alive - is something that I've found as a moviegoer only works out of absolute necessity, and even then that's still dependent on HOW it's used.
Take TRON Legacy, for example. Something about the digital replica of Jeff Bridges in his younger days felt off to me when it was used for the flashbacks of Flynn, yet it came across more effectively when it was used for Clu. Granted, that's just me, since there are times when I find something's inherent phoniness actually works to its advantage: for example, I don't think the original JAWS would work as well if Spielberg tried to "Special Edition" it with an ILM-issue CGI shark, since I find the mechanical Bruce far more implacably terrifying than even the live-footage great white that the Taylors got, and that's due largely to Bruce actually BEING a mindless machine. Same with the giant ants in THEM!, too (that and that great chattering sound effect of theirs).
Superman Returns was similar in some ways with the digital Brando, since the Jor-El hologram as originally depicted back in 1978 was ALREADY being used to represent a character long dead by that point in the story. I mean, it felt a little odd, obviously, since Brando himself was dead by the time SR was being made, but I was never really troubled by that particular use of it.
I also think digital de-aging is best left to brief sequences, like with Ant-Man. I think it helped that we don't really see the de-aged Michael Douglas in any other scene except the opening flashback. It's like a time-travel movie; if you're gonna have two versions of the same character on the screen for a
substantial amount of time, it'd probably still come across less creepy either using the same actor in age make-up for the "older" version" (a la BTTF), or casting somebody else entirely - although preferably with at least SOME resemblance - to play the "younger" version (a la MIB3).
I don't think we need worry about Digital Zombie Bogart, Marilyn or Mork haunting screens anytime soon (since I think their respective estates or whatever's still around that would pass for them would probably have something to say on the matter, too). B'sides, they only use digitally-resurrected celebrities in TV commercials to sell junk food, so I think we're safe.
