It's funny you mention this because I was about 10 or 11 when the MiB movie came out and really into alien stuff. When I heard about the movie before it came out I researched the men in black on the early internet and it was some really creepy stuff. When I finally saw the movie it was a much different tone than I expected. I agree it would be a great candidate for a 'serious' reboot that takes a darker approach.