Calling a horror novel "too scary" goes right up there with complaining that the plot lasted until the last page. A horror novel is *supposed* to be scary! My former publisher had a list of anything readers had complained about, and if it was in a book, they made sure to list it in the description. The people who wanted those elements in a book searched for them, and those who didn't, avoided them. It made for much higher reader loyalty, and they were willing to risk books by new authors because there weren't going to be any unpleasant "surprises".