1. Deaths
One thing that J.K Rowling does very well in her books and this is something she should be admired for as a writer, is that she is never afraid to kill off her main characters. I can think of countless main characters that have died in the Potter books: Sirius Black, Severus Snape, Albus Dumbledore, Fred Weasley, Cedric Diggory and Remus Lupin to name but a few. In Lord Of The Rings, what is the magic number? Two? Boromir & Theoden are the only main protagonists that I can think of that actually die in the trilogy. Even then, Boromir dies so soon before we even know of the Faramir-Boromir subplot so it really has no impact emotionally and Theoden is an aging king anyway and the audience had no real connection with him. Even Gandalf we think has been killed off, but it seems as though Tolkien writes by the ethos of, "One does not simply kill off their main character," and he just can't face losing his beloved wizard. So in this sense, JK Rowling has twice the balls of Tolkien as an author, in that she understands death are needed to further the plot of the series. I must confess that in The Lord Of The Rings there are plenty of dead CGI warriors, (Orcs and Urukhai alike), but who actually cares about those deaths? What impact does that have on the rest of the trilogy? None whatsoever. Whereas in Harry Potter, one of the major themes of the whole series is death. Even before the movie narrative starts, we are aware of the death of Harry's parents and this actually has a major impact on the whole 7 books. In this way, the plot of Harry Potter in my opinion becomes a whole lot more believable. J.K Rowling understands that for fantasy literature to work, casualties must occur on both sides and Tolkien doesn't seem to understand this.