From my viewpoint, Extraction seems like a gametype in Matchmaking where you are given near 0 incentive to play: unless you're doing Commendations for Player, Weapon, and Vehicles.
I know people like Extraction, but It's not something I like very much imo. I'm a kind of person who needs a reason to play the game in order to play (like Achievements or Commendations relating to the Gametype). If there is nothing there, then I'm out.
And I think Extraction does have a good concept, but like Bnus said... I also think 343i could have done better with it.