One thing I've just noticed which gives me new-found respect for the art department on TPM is that the costume designers seem to have made copious reference to the unused character concepts Moebius did for Willow.
The Jedi hairstyle that Obi-Wan Kenobi sports in the TPM storyboards from the rough-draft period is a dead ringer for Madmartigan's hair in the earlier movie (which was based on a Moebius design).
Likewise, Moebius's concept drawings for Sorsha (Willow's secondary villain and Madmartigan's love interest) feature her wearing a white Noh mask with ornamental red markings. Guess what shows up in the prequels as makeup on Amidala's face?
Plus, one of the drawings for Sorsha features her with a long blonde ponytail and an otherwise shaven head. That hairstyle got reused for bounty hunter Aurra Sing (who also received Luke's very long rifle from Ralph McQuarrie's old drawings).
If nothing else, it shows the TPM character designers were quite impressed by Moebius's earlier work for Lucasfilm. Too bad Lucas and Ron Howard didn't actually use most of his designs for Willow itself...