Ever since Star Wars used it, a vast majority of film, television, animation, and video games felt the need to incorporate this completely out of place scream.
Recently I was watching Kingdom of Heaven by Ridley Scott, and in the middle of the Siege Battle for Jerusalem, I heard a Wilhelm Scream. It completely took me out of the mood watching the movie because Kingdom of Heaven isn't a humorous/lighthearted movie. Its serious, bloody, and moody.
But I also conceed that you can still use the Wilhelm Scream, just use it where its appropriate because the scream now feels like a joke, a punchline. It has no business in a movie like Kingdom of Heaven.