I have a problem with milking. Almost every game that has been milked, I have lost interest in them, Assassin's Creed, Halo (haven't even played any other than 3, will probably get 4 since it looks finally a bit different), Call of duty.
Usually milked games DO NOT retain their quality, they just use the same template and a different story. Fallout New Vegas was the only exception, I preferred the level design in that game over fallout 3.
Dead Space 2 is a good example of a well done sequel which introduced some good new concepts without removing older ones. Most CoD, Assassin's creeds, all have similar concepts and none new ones so it does get boring after a while. I got bored while playing both MW2 and AC Brotherhood.
I also haven't got a single FIFA game since ages.
