so far with the art style.
people said, the 5th movie was kind of the changing point, so this could have been the last one of the korean team. and well, americans are, let's say, likely to overreact when it comes up to the degree of suspense in children movies.
you probably know: 11 minutes of the 1988 movie were cut out because of horror-stuff, as they said.
finally i'm tempted to say that the amis took the suspense away. that'd be my conclusion.
edit: i have to correct myself. after The Secret of Saurus Rock the art work wasn't taken over by an american, but a taiwanese studio. just found it out.