Why I Am Pre-ordering Call Of Duty: Modern Warfare 3

Personally to me it still seems like an overly glorified map pack for MW2. They keep re-releasing the same game over and over each year, only with minor tweaks and changes to the game over all. From what I can tell it looks like the same engine from MW2, correct me if I’m wrong, which tells me they don’t care much about making new big changes to the series, they just want a quick buck from it milking it for all it’s worth. If they decided to release a new COD every 2-3 years and support each one more, halo would be a good example of this with a newer updated engine each game, I would be more inclined to continue buying and playing them.