A question to a question, if you ask if someone is a bad writer, in what respect? JKR is highly readable to multiple levels of reading and appealing to an audience far broader than the intended target. My brother was an english major and has had a long career in journalism. I think his dream was to be a novelist, but I recall conversations with him about popular novelists and his point that there were many successful novelists out there that were technically not good writers, but in the great scheme of things it just doesn't matter. Appeal matters. JKR brought a roller coaster of joy, suspense, escapism etc. to a huge audience. I for one am certainly willing to forgive a few world building missteps. I've been trying to write a novel for some time now, and I'me forever going backwards and correcting new inconsistencies that i've inadvertently created. I was actually always impressed how book after book, JKR could create layers that I could incorporate into my mental model of the world at hand. Consistency is really hard in a constructed world. I think that anyone who argues that JKR is a bad writer has a chip on their shoulder. Sure you can be a technical purist if you want to, but in the end it doesn't matter to anyone but the snobs. Some would say it's success that matters, but I think it's how many people you touch and you can't argue that JKR hasn't touched a great deal of people. Sorry if I come off as a literary Philistine...