4. Assignments
The assignment system was one of the smartest things implemented into Battlefield 3 post-launch. The idea is just perfect. Make people do specific tasks to unlock a weapon, then having one assignment done unlocks the next one. Huh, like school. Anyway, the new assignments were brought into the game with the release on Back to Karkand, and each DLC brings a few more. Premium members also get new assignments each month that unlock new camo's and soldier upgrades. The system just works, and the difficulty is fine. Except the EOD Bot kill assignment for the MTAR-21. That one sucked.