I quite like the zany Josh Kirby book covers, but I could see why people would want the neater, more formal covers. It would also lead more superficial people to read Terry's books. I've lost track of the people I've overheard, looking at Terry's book covers (not even reading the blurb / synoposis!), and saying something like 'that's not really the kind of book I read!'
Their loss, really. I've also overheard some people saying, 'No, that's a Children's book, dear. Look at the cover.'
They've obviously never heard of the quote : "You have to write whichever book it is that wants to be written. And then, if it's going to be too difficult for grown-ups, you write it for children". I find more depth, philosophy, science and truth in TP's novels than in most so-called 'classics' - most of which are a huge disappointment.