Should a movie be judged from the time of it's release, or how well it stands today?
Both.
For the most part, if an "old" film doesn't stand up today people won't watch it anyway. But enjoying an old film requires an understanding of the "culture" of the time. Take a film like "It Happened One Night" with Claudette Colbert and Clark Gable, directed by Frank Capra.
http://www.imdb.com/title/tt0025316/
http://en.wikipedia.org/wiki/It_Happened_One_Night
Very, very tame by todays standards, but was considered quite scandalous when it was released - an unmarried man and woman traveling together and - OH MY GOD! - sharing a room, even though there is a blanket between them. It was also full of sexual innuendos that were familiar in the 30s but we miss today. BTW, it's one of the films that set the "pattern" for all the RomComs that came afterwards, up to and including today. Oh, and it won five (5) Oscars - Best Picture, Director, Actor, Actress, and Screenplay. Yet how many here on IndieTalk have seen it? (In the interests of full disclosure I am a big Capra fan; I love Capra-Corn!)
What about "Star Wars"? The CGI, etc. is pretty primitive by todays standards, same old heroes journey plot; does it still hold up?
How about a cult classic like "Eraserhead;" does it still hold up?
Beauty is in the eye of the beholder. A great story is a great story. What attracts people is how the story is told, and many reject "old" versions of the story as they don't understand the cultural references, or find the medium "primitive."