Battlefield: Bad Company 2 is still a great shooter to this day. However, once you reach a certain point there's not much to unlock anymore. That wouldn't be such a problem, mind you, had this "certain point" not arrived so quickly. Needless to say, the proverbial "hanging carrot" was not really out of arm's reach, and some people found this to be rather...lame.
DICE is fixing all that with Battlefield 3, which is said to have "10 times the hardware unlocks spread over weapons, weapon attachments, gadgets, and a huge unlock tree for vehicles alone."
On top of the equipment unlocks, ribbons and medals also return, rewarding players for performing a variety of feats on the battlefield, such as capturing "X" number of bases, reviving "X" number of teammates, or sniping "X" number of enemies. Service Stars are a new concept for the series, and from the sound of it they seem to resemble the idea of Call of Duty's Prestige mode, or continuing to rank up even past the highest point. My theory on this is backed up by the Battlefield Blog mentioning you can be a Colonel--highest rank-- with 100 Service Stars on your record, further proving it is reminiscent of Prestige mode. Service Stars can also be added on your weapons, kits, vehicles, as well as your overall rank.
Akin to Bad Company 2, the more you play with a certain kit or weapon loadout, the more unlocks you will gain for that specific item. Additionally, ranking up your overall level will also unlock items, either for specific classes or for general use.
DICE hopes that all of these unlocks and goals will make players have "as much fun with [Battlefield 3] in 2013 as on launch day." I'm sure it will, DICE, I'm sure it will.