The Wikipedia entry for actor refers to a style guide that advocates a preference of actor over actress:
"When the Observer and the Guardian published their new joint style guide in 2010, it stated "Use ["actor"] for both male and female actors; do not use actress except when in name of award, e.g. Oscar for best actress." The authors of the style guide stated that "actress comes into the same category as authoress, comedienne, manageress, 'lady doctor', 'male nurse' and similar obsolete terms that date from a time when professions were largely the preserve of one sex (usually men). As Whoopi Goldberg put it in an interview with the paper: 'An actress can only play a woman. I'm an actor – I can play anything.'"
The terminology section then goes on discussing the issue inconclusively. The intent to prefer actor over actress is expressed often enough in the media and elsewhere. (Here is an ELU post on the topic and here is a post discussing a related issue.)
I wonder whether it would be natural or appropriate to apply this change retroactively, i.e., when referring to popular female actors of the past decades, who in their time were described as actresses and were presumably happy with that term.
The question may boil down to whether the profession label, such as actor, depends primarily on how the subject of the label choose to describe themselves, or whether, on the other hand, it is predominantly imposed by others.
Would it be natural or appropriate to think of Greta Garbo as a great actor, rather than a great actress? (Currently her Wikipedia entry describes her as an actress).