84 is a really good meta-score, but I do understand that some people expected more from a Halo game. It would be akin to a 3d Mario(or mainline Zelda game) getting mid-80s, or Uncharted getting mid-80s. First party exclusives tend to be held to a higher expectation for some odd reason whereas no one really batted an eye when Black Ops 3 got an 81.