when it comes to Online, unlocks is the new craze every game must have. This skinner box technique were rewards are given for playing the online game has reach massive amounts in cod with black ops having so much rewards its way over the top.
While they are great to have an goal i dislike the xp grinding just for the unlocks. But playing Shogun 2: Total War online they have one of the best online unlocks system going around.
First off you dont need to be an certain level or get certain amount of xp to get the major unlocks such as new units and perks(retainers) and you collect such unlocks by having each player have an map of Japan which is the same as the campaign map and you select an starting point and you can move from that starting point your army to the next region. An if you win an battle on that region you get the reward.
It creates an far better unlock goal and an makes you have to plan which region do you capture to get the next desired unlock as fast as possible to give you the leg up in battles.
Its an far more interesting and better way then simply gain some points then at an certain point get the unlock. An while not all games could do the same thing but the concept of choosing which unlock to go for then unlocking it when you win, is something developers should look into to give there game an difference in the online space.
edit: Mods please move wrong forum, made so many different forums its hard.
Of Course That's Just My Opinion, I Could Be Wrong