I think the big problem is that a lot of the newer versions of these films don't really have much to add to the originals. I can't see YOU'VE GOT MAIL as having anything to add to the original SHOP AROUND THE CORNER -- Tom Hanks and Meg Ryan can't hope to add depths that weren't explored by James Stewart and Margaret Sullavan.
On the other hand, Huston's film of THE MALTESE FALCON does what neither of the preceding films had done -- played the story as a straight up dramatic detective thriller with high stakes. The version immediately before it, SATAN MET A LADY, plays the story for particularly lame romantic comedy. The other version with Cortez, now known as DANGEROUS FEMALE, is a real botch: a pre-Code catastrophe where Ricardo Cortez's Sam Spade is so busy chasing dames that you never for a minute believe he's got what it takes to sort out the strands of plot -- his brain is clearly not his favorite organ.
Huston's THE MALTESE FALCON ups the ante considerably, playing the story for the dark proto-noir that it is.
Likewise Hitchcock's remake of MAN WHO KNEW TOO MUCH, which pays a lot more attention to the issues in the main characters' clearly trouble marriage than the earlier film, and is a far richer film for it. The horrifying moment when Stewart extorts Day into taking sleeping pills before telling her their son has been kidnapped would have been unthinkable in the earlier version.
"If they can get you asking the wrong questions, they don't have to worry about the answers." Thomas Pynchon, GRAVITY'S RAINBOW
"Reality is that which, when you stop believing in it, doesn't go away." Philip K. Dick
My blog: http://www.roscoewrites.blogspot.com/