None of the segments improve on the originals exactly, but some are sufficiently different that they are worthwhile takes.
Landis section: 0 stars (1 if you ignore real life situation)
It's a stupid, hacky racism-is-bad story which does nothing interesting with the premise, for which real people died filming.
Spielberg/Kick the Can: 2 stars
Changes the message somewhat by making the Crothers character so magical that he goes from place to place, introducing the idea that they shouldn't be young…