It's not the art that's the isses. It's that this has been chosen for 4k treatment. Of all the possible films to showcase 4k they chose a 30 year old puppet movie. At best you'll see how crappy it looks in more detail.
A whole raft of 4KUHD films have been/are about to be released here in the U.K. and granted nearly all are of more recent vintage than LABYRINTH (such as DEADPOOL, THE REVENANT, GHOSTBUSTERS 1 & 2 and GHOSTBUSTERS 1 - 3 COLLECTION, SICARIO, HANCOCK, CREED, CONCUSSION, THE MARTIAN, SALT, THE CRIMINAL, PAN, CHAPPIE, KINGSMAN, THE FIFTH WAVE, BATMAN V. SUPERMAN: DAWN OF JUSTICE, MAN OF STEEL, DIVERGENT, GRIMSBY, THE EXPENDABLES 3, THE ANGRY BIRDS MOVIE, JASON BOURNE, IN THE HEART OF THE SEA, POINT BREAK (2015), ID 4, AMAZING SPIDER-MAN 2 (2014), PINEAPPLE EXPRESS, SMURFS 2, MAD MAX (2015), LEGO MOVIE, JOY, FANTASTIC 4 (2015), LIFE OF PI, X-MEN: DAYS OF FUTURE PAST, SCORCH TRIALS, EXODUS: GODS AND KINGS, THE MAZE RUNNER, HITMAN: AGENT 47, SUICIDE SQUAD, X-MEN: APOCALYPSE, ICE AGE: COLLISION COURSE, ID: RESURGENCE) there are still a few "oldies" there amongst the newer stuff.
Can't think why they decided on LABYRINTH 4K as the first U.K. steelbook in the same way that I can't fathom why SWEENEY TODD was picked as the first U.K. steelbook back in May, 2008 but in this case at least the artwork is stellar.
However, possible reasons might include:-
a) It's a bit of a cult classic for a certain generation even though it didn't do well at the box office with reported grosses of about half its budget.
b) 30th Anniversary with other special editions and a giftset planned with new Extras/Interviews.
c) Released in the same year as the death of its star, David Bowie, a music legend if ever there was one.
It could also be argued that ALIENS or one of the other big hitters of 1986 - such as TOP GUN, PLATOON, CROCODILE DUNDEE, THE GOLDEN CHILD, RUTHLESS PEOPLE, FERRIS BUELLER'S DAY OFF, DOWN AND OUT IN BEVERLEY HILLS - or my personal favourite of the bunch STAND BY ME - would have made for a more satisfying 4KUHD 30th Anniversary Steelbook Edition release but then again "one man's meat is another man's poison" . . . apart from the fact that some of these have not even had a BD release here in the U.K. and STAND BY ME already has a regular steelbook coming out in not more than a month's time . . . but not forgetting that LABYRINTH has already had a regular steelbook release in February of this year.