Pro Football Focus does a good job of going beyond the traditional stats to pinpoint the players doing well and we saw that throughout the 2010 season with Jamaal Charles and his awesomeness.
As a unit they (Chiefs defense) registered two sacks, two hits, and 12 pressures. Take Hali out of that working group and that number drops to just five pressures. As a comparison, Hali registered pressure in some form 11 times on 30 pass rushes - better than 1-in-3 opportunities. The rest of the Kansas City defenders got their five on 102 combined rushes, worse than 1-in-20.
So he's kind of important to the team.
Hali's importance is also showing up in the record books. He notched two sacks on Sunday, which put him into fifth place on the Chiefs all-time sack list with 45.5 sacks. Mike Bell is in fifth place with 51 so, barring injury, you'd think Hali gets there.