I liked his books quite a lot as a kid, and haven't prevented any children in my care from accessing them. But on revisiting as an adult there is a kind of... meanspiritedness to them. It's hard to describe but almost like, spiritual viciousness or a deep nasty pessimism about people.
Part of this may be why they appeal to children anyway. I didn't consciously notice as a kid but I suspect they registered as slightly transgressive in some way, and were alluring for that reason. Anyway none of the edits really address that, or could. To a significant extent that feeling is a fundamental part of the books and can't be removed.