Here's another thing about the covers. Although I personally dislike the Josh Kirby covers because of the style, I noticed a while back that most of them have a hidden image, like the pictures by Arcimboldo. Arcimboldo specialized in making pictures of people that were actually pictures of heaps of fruit and objects. They used the human tendency to see a shape in a heap of objects and see it as a face. When I look at a Kirby cover, if I take off my glasses and blur the image I can find the hidden face. It's most obvious to me in the cover for Feet of Clay, but I've found it in almost all of them. To some extent, Darrell K.Sweet used to do that in at least some of the American paperback covers. Sometimes it's easiest to see in a thumbnail image.
In order to get the shapes right for the effect, the artists had to do odd things to the characters, which explains some of the weirdnesses.
I still prefer the simple iconic covers, but I wanted to point this out because they went to so much trouble to do it, I think it ought to be known.
ETA: Paul Kidby seems to be continuing with the concept.