I think there's a difference between coming in and changing everything, which is what Straczynski did for Superman
(suddenly it wasn't about a hero fighting villains, it was about a hero walking across America) and moreso Wonder Woman
(in which he basically re-did everything about Diana) and having a new writer come in.
Sometimes a writer comes in and doesn't change that much, but really improves the quality of the storytelling. Rarely, it seems, they get someone excellent to follow another excellent writer's tenure on a book. More often we seem to get "really awesome writer" then a string of "really lame writers."
Going back to Hickman, I don't think he necessarily came in and changed a lot, rather he seemed to come in and write really good stories without changing much of the status quo of the book (well, up until the "3" storyline). And to write an awesome, seminal run, he didn't try to re-invent the wheel. He didn't try to go back and mess with the origins of the characters. He just wrote the best versions of the characters he could.
The problem with those who do come in and change things is that, for one reason or another, it never lasts. The common urge is to blame either the fans ("Comic fans hate change!") or the company ("The Company needs to keep the version of the character that the public is familiar!"), but the end result is the same. A company, like Marvel brings in Grant Morrison who makes several major changes, most of which are wiped out, retconned, or forgotten about after he leaves.
I wish the comic companies would just focus on finding the best writing and art team for the book and didn't try to reinvent the wheel everytime a creative team left.