They judge the game by playing time,meaning they want you to play and grind for the weapon(s) you're rooting to get.As you see last Tuesday bungie decided to decrease valus taurc health by 1/3.Why?Because there wasn't many people doing that strike and it took 22 minutes for the normal mode.So they want you to grind for those weapons people want it's playing time and the more you play the more weapons you'll get.